Re: [Parquet] ALP Encoding for Floating point data

[PRATEEK GAUR <pr...@gmail.com>]

Hi team,

Quick update re: the C++ implementation.
Thanks to all the reviewers, we merged the C++ implementation today.
There are a few follow-up items that I'll address in a subsequent PR.

Thanks
Prateek

On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <vi...@gmail.com> wrote:

> Quick update re: the Java impl. Thanks for the feedback, on
> https://github.com/apache/parquet-java/pull/3397, Russel! I pulled
> https://github.com/apache/parquet-java/pull/3791 into its own PR (thanks
> for the quick approval too, Gang). Assuming no objections, I think we can
> merge #3791, and then go ahead of #3397.
>
> Thanks,
> Vinoo Ganesh | vinoo.ganesh@gmail.com
>
> <Vi...@gmail.com>
>
>
> On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <pr...@gmail.com> wrote:
>
> > [Rust] Awesome thanks Andrew, Kostas and Devin.
> > [Java] Thanks Gang for the feedback on Java PR.
> > [C++] Thanks Gang for another round of feedback on the C++ one.
> > [Go] Arnav and I will be working on the golang impl this week.
> >
> > This is great progress all around.
> >
> > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <vi...@gmail.com>
> > wrote:
> >
> > > Thanks all - I'm addressing Gang's comments on
> > > https://github.com/apache/parquet-java/pull/3397 now, so hopefully
> well
> > > also be in a good state for merging the java implementation soon.
> > >
> > > Thanks,
> > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > >
> > > <Vi...@gmail.com>
> > >
> > >
> > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <an...@gmail.com>
> > wrote:
> > >
> > > > We just merged the Rust implementation[1] from Kosta and Devan. With
> > the
> > > > imminent release of Parquet Format 2.14.0 I think we'll be well on
> our
> > > way.
> > > >
> > > > Thanks again for pushing this along,
> > > > Andrew
> > > >
> > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> > > >
> > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <pr...@gmail.com>
> > wrote:
> > > >
> > > > > Hi team,
> > > > >
> > > > > Thanks Micah for multiple rounds of review and thanks Gang for
> > taking a
> > > > > look at the PR and giving feedback. I've addressed all comments in
> > the
> > > > PR.
> > > > > Looking forward to the next round of feedback (or approval). Would
> > like
> > > > to
> > > > > get it in soon.
> > > > >
> > > > > https://github.com/apache/arrow/pull/48345/changes
> > > > >
> > > > > With this done and after talking to Arnav, I plan to spend some
> time
> > on
> > > > the
> > > > > ALP implementation in the arrow-go repository helping spread the
> > > support
> > > > to
> > > > > more languages.
> > > > >
> > > > > Best
> > > > > Prateek
> > > > >
> > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <pr...@gmail.com>
> > > wrote:
> > > > >
> > > > > > Thanks Divjot for bringing it up.
> > > > > >
> > > > > > I was under the same impression as Russell and Andrew that we'd
> > have
> > > it
> > > > > > flag gated.
> > > > > > With the new versioning proposal 'preview' might be a good tag
> for
> > > it.
> > > > > >
> > > > > > Best
> > > > > > Prateek
> > > > > >
> > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> > andrewlamb11@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > >> Div: Here is a proposal to mark ALP in Preview: [1] (using a
> > comment
> > > > in
> > > > > >> the
> > > > > >> spec section).
> > > > > >>
> > > > > >> Russel: That is my understanding as well.
> > > > > >>
> > > > > >> Hopefully we are able to formalize the versioning process
> shortly
> > so
> > > > we
> > > > > >> can
> > > > > >> formalize the notion of "preview"
> > > > > >>
> > > > > >> Andrew
> > > > > >>
> > > > > >>
> > > > > >> [1]: https://github.com/apache/parquet-format/pull/604
> > > > > >>
> > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> > > > > >> russell.spitzer@gmail.com>
> > > > > >> wrote:
> > > > > >>
> > > > > >> > I thought we had agreed it would be merged, and features like
> > this
> > > > > would
> > > > > >> > be feature flag gated. So a V-Old writer could always opt in
> to
> > > > using
> > > > > >> this
> > > > > >> > encoding but that must be a conscious effort if you are not
> > using
> > > > > VNext
> > > > > >> of
> > > > > >> > Parquet. If you are on V-Next the writer can choose to use ALP
> > > > > whenever
> > > > > >> it
> > > > > >> > likes without user intervention.
> > > > > >> >
> > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via dev <
> > > > > >> > dev@parquet.apache.org> wrote:
> > > > > >> >
> > > > > >> >> Yes, that’s my understanding as well. However, as you noted,
> > the
> > > > > >> >> versioning
> > > > > >> >> discussion is still in early stages and hasn’t prescribed
> > > concrete
> > > > > >> >> mechanisms yet. If ALP goes into parquet-format 2.14.0,
> there’s
> > > no
> > > > > >> >> indication that it’s in preview or that writers shouldn’t use
> > it
> > > by
> > > > > >> >> default
> > > > > >> >> yet. Given that we’ve held off on merging other incompatible
> > > > changes
> > > > > >> (e.g
> > > > > >> >> removal of path_in_schema) until the versioning discussion
> > > closes,
> > > > my
> > > > > >> >> preference would be to leave ALP un-merged for the time being
> > as
> > > > > well.
> > > > > >> >>
> > > > > >> >> — Div
> > > > > >> >>
> > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> > > andrewlamb11@gmail.com>
> > > > > >> wrote:
> > > > > >> >>
> > > > > >> >> > After re-reading Julien's Versioning Proposal, my
> > understanding
> > > > is
> > > > > >> that
> > > > > >> >> if
> > > > > >> >> > we adopt that system, we will somehow mark ALP in "Preview"
> > in
> > > > > >> >> > parquet-format for release Version 3.
> > > > > >> >> >
> > > > > >> >> > The versioning document doesn't seem to proscribe the
> > > particular
> > > > > >> method
> > > > > >> >> > for annotating "preview" features -- I think clearly
> marking
> > > them
> > > > > as
> > > > > >> >> such
> > > > > >> >> > in parquet.thrift as well as reflecting that on the
> > > > > >> >> > https://parquet.apache.org/docs/file-format/versions/ page
> > > > somehow
> > > > > >> >> would
> > > > > >> >> > be adequate.
> > > > > >> >> >
> > > > > >> >> > Andrew
> > > > > >> >> >
> > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> > > > > andrewlamb11@gmail.com
> > > > > >> >
> > > > > >> >> > wrote:
> > > > > >> >> >
> > > > > >> >> >> In my mind ALP is in the same position as other encodings
> > that
> > > > > were
> > > > > >> >> added
> > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non floating
> > point
> > > > > types)
> > > > > >> >> >>
> > > > > >> >> >> That is to say it will be available in the latest open
> > source
> > > > > >> writers
> > > > > >> >> and
> > > > > >> >> >> readers, but realistically not widely used in the
> ecosystem
> > > > where
> > > > > >> >> >> compatibility is a concern (a large part)
> > > > > >> >> >>
> > > > > >> >> >> I view Julian's work[2][3] to gather consensus on how to
> > name
> > > > > >> >> >> combinations of features (e.g. "versions") as the
> mechanism
> > by
> > > > > >> which we
> > > > > >> >> >> will accelerate the adoption of this change (along with
> > other
> > > > > >> forward
> > > > > >> >> >> incompatible changes) across the ecosystem.
> > > > > >> >> >>
> > > > > >> >> >> > Will we exclude this change when cutting parquet-format
> > > > v2.14.0?
> > > > > >> >> >>
> > > > > >> >> >> No I don't think so -- I would expect it to go out in the
> > next
> > > > > >> >> >> parquet-format version as do other changes in the spec.
> > > > > >> >> >>
> > > > > >> >> >> Andrew
> > > > > >> >> >>
> > > > > >> >> >> [1]:
> https://parquet.apache.org/docs/file-format/versions/
> > > > > >> >> >> [2]:
> > > > > >>
> https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> > > > > >> >> >> [3]:
> > > > > >>
> https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> > > > > >> >> >>
> > > > > >> >> >>
> > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora via dev <
> > > > > >> >> >> dev@parquet.apache.org> wrote:
> > > > > >> >> >>
> > > > > >> >> >>> Hi Andrew,
> > > > > >> >> >>>
> > > > > >> >> >>> How does this interact with the ongoing versioning
> > > discussion?
> > > > > >> Given
> > > > > >> >> that
> > > > > >> >> >>> new encodings are not forward compatible, I would assume
> > ALP
> > > is
> > > > > >> >> included
> > > > > >> >> >>> in
> > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to me how that
> > > works
> > > > if
> > > > > >> it's
> > > > > >> >> >>> merged to the parquet-format master branch now. Will we
> > > exclude
> > > > > >> this
> > > > > >> >> >>> change
> > > > > >> >> >>> when cutting parquet-format v2.14.0?
> > > > > >> >> >>>
> > > > > >> >> >>> -- Div
> > > > > >> >> >>>
> > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
> > > > > >> andrewlamb11@gmail.com>
> > > > > >> >> >>> wrote:
> > > > > >> >> >>>
> > > > > >> >> >>> > Hello,
> > > > > >> >> >>> >
> > > > > >> >> >>> > As an update, thanks to the epic work from many
> > > contributors,
> > > > > >> >> >>> especially
> > > > > >> >> >>> > Prateek, I just merged the parquet-format change for
> > > ALP[1].
> > > > We
> > > > > >> >> plan to
> > > > > >> >> >>> > make additional editorial The remaining items I know of
> > are
> > > > > >> merging
> > > > > >> >> the
> > > > > >> >> >>> > examples from parquet-testing[2], and then of course
> the
> > > > > various
> > > > > >> >> >>> > implementations
> > > > > >> >> >>> >
> > > > > >> >> >>> > Thanks again everyone. This is a great step forward
> > > > > >> >> >>> > Andrew
> > > > > >> >> >>> >
> > > > > >> >> >>> > [1]: https://github.com/apache/parquet-format/pull/557
> > > > > >> >> >>> > [2]:
> https://github.com/apache/parquet-testing/pull/100
> > > > > >> >> >>> >
> > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le Dem <
> > > > > julien@apache.org
> > > > > >> >
> > > > > >> >> >>> wrote:
> > > > > >> >> >>> >
> > > > > >> >> >>> > > It was also in my spam folder... :(
> > > > > >> >> >>> > > I've seen a bunch of apache list emails go to my spam
> > > > > recently.
> > > > > >> >> >>> > >
> > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell Spitzer <
> > > > > >> >> >>> > > russell.spitzer@gmail.com>
> > > > > >> >> >>> > > wrote:
> > > > > >> >> >>> > >
> > > > > >> >> >>> > > > Yes, my hope was that my vote would kick it out of
> > spam
> > > > but
> > > > > >> we
> > > > > >> >> >>> > definitely
> > > > > >> >> >>> > > > had two other votes that also went to spam for me.
> > > > > >> >> >>> > > >
> > > > > >> >> >>> > > > For anyone looking the thread is here
> > > > > >> >> >>> > > >
> > > > > >> >>
> > https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> > > > > >> >> >>> > > >
> > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah Kornfield <
> > > > > >> >> >>> > emkornfield@gmail.com>
> > > > > >> >> >>> > > > wrote:
> > > > > >> >> >>> > > >
> > > > > >> >> >>> > > > > I've seen other's votes not go to spam, so
> > hopefully
> > > > > people
> > > > > >> >> will
> > > > > >> >> >>> see
> > > > > >> >> >>> > it
> > > > > >> >> >>> > > > in
> > > > > >> >> >>> > > > > there inboxes (or see this thread and look in
> there
> > > > > spam).
> > > > > >> >> >>> > > > >
> > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM PRATEEK GAUR <
> > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > >> >> >>> > > > wrote:
> > > > > >> >> >>> > > > >
> > > > > >> >> >>> > > > > > Okay,
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > > > I sent out the voting email yesterday and so
> far
> > > I've
> > > > > >> heard
> > > > > >> >> >>> from 3
> > > > > >> >> >>> > > > people
> > > > > >> >> >>> > > > > > that it ended up in their "spam folder". Dev
> VPN
> > to
> > > > be
> > > > > >> >> blamed
> > > > > >> >> >>> for
> > > > > >> >> >>> > > it?.
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > > > What's the protocol here?
> > > > > >> >> >>> > > > > > I let people hunt for the email in their spam
> > > folder
> > > > or
> > > > > >> send
> > > > > >> >> >>> out
> > > > > >> >> >>> > > > another
> > > > > >> >> >>> > > > > > one?
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > > > Best
> > > > > >> >> >>> > > > > > Prateek
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM PRATEEK GAUR <
> > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > >> >> >>> > > > > wrote:
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > > > > Hi team,
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > Vinoo has added the tests which were
> requested
> > in
> > > > the
> > > > > >> last
> > > > > >> >> >>> round
> > > > > >> >> >>> > of
> > > > > >> >> >>> > > > > > review.
> > > > > >> >> >>> > > > > > > In his own words.
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > "
> > > > > >> >> >>> > > > > > > The extreme value tests Micah wanted are done
> > and
> > > > > >> pushed.
> > > > > >> >> I
> > > > > >> >> >>> added
> > > > > >> >> >>> > > > > > coverage
> > > > > >> >> >>> > > > > > > for values that need the full FOR bit width
> > after
> > > > the
> > > > > >> >> frame
> > > > > >> >> >>> of
> > > > > >> >> >>> > > > > reference
> > > > > >> >> >>> > > > > > is
> > > > > >> >> >>> > > > > > > applied: 64-bit (the case where the signed
> max
> > > > minus
> > > > > >> min
> > > > > >> >> >>> > > subtraction
> > > > > >> >> >>> > > > > > > overflows), 63-bit (the non-overflow case),
> and
> > > > > 32-bit
> > > > > >> for
> > > > > >> >> >>> > floats.
> > > > > >> >> >>> > > > All
> > > > > >> >> >>> > > > > > > lossless with zero exceptions. I also
> verified
> > > them
> > > > > >> >> through
> > > > > >> >> >>> Arrow
> > > > > >> >> >>> > > C++
> > > > > >> >> >>> > > > > ALP
> > > > > >> >> >>> > > > > > > reader (the local build), so the Java-written
> > > > extreme
> > > > > >> >> columns
> > > > > >> >> >>> > > decode
> > > > > >> >> >>> > > > > > > correctly in C++, bit-exact against the
> > expected
> > > > > >> values."
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > State of the PR (#3397):
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I pulled
> > master
> > > in
> > > > > and
> > > > > >> >> >>> resolved
> > > > > >> >> >>> > > the
> > > > > >> >> >>> > > > > > >    conflicts).
> > > > > >> >> >>> > > > > > >    - 41 of 44 review threads resolved. The 3
> > > > > remaining
> > > > > >> are
> > > > > >> >> >>> > > > intentional:
> > > > > >> >> >>> > > > > > >    one deferred perf nit, one that stays open
> > > until
> > > > > >> >> >>> > parquet-format
> > > > > >> >> >>> > > > > ships
> > > > > >> >> >>> > > > > > ALP,
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > "
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > With this both the
> > > > > >> >> >>> > > > > > > 1) C++ PR :
> > > > > >> >> >>> https://github.com/apache/arrow/pull/48345/changes
> > > > > >> >> >>> > > > > > > 2) Java PR :
> > > > > >> >> >>> https://github.com/apache/parquet-java/pull/3397
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > Are cross language tested and range of test
> > > > > scenarios.
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > Best
> > > > > >> >> >>> > > > > > > Prateek
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM PRATEEK GAUR
> <
> > > > > >> >> >>> prtkgaur@gmail.com
> > > > > >> >> >>> > >
> > > > > >> >> >>> > > > > wrote:
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > >> Thanks Matt,
> > > > > >> >> >>> > > > > > >>
> > > > > >> >> >>> > > > > > >> I'll be on it this week.
> > > > > >> >> >>> > > > > > >>
> > > > > >> >> >>> > > > > > >> Best
> > > > > >> >> >>> > > > > > >> Prateek
> > > > > >> >> >>> > > > > > >>
> > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM Matt Topol <
> > > > > >> >> >>> > > zotthewizard@gmail.com>
> > > > > >> >> >>> > > > > > >> wrote:
> > > > > >> >> >>> > > > > > >>
> > > > > >> >> >>> > > > > > >>> There is also the Go implementation
> submitted
> > > by
> > > > > >> Arnav (
> > > > > >> >> >>> > > > > > >>>
> https://github.com/apache/arrow-go/pull/704)
> > > > which
> > > > > >> is
> > > > > >> >> >>> waiting
> > > > > >> >> >>> > > for
> > > > > >> >> >>> > > > > > >>> updates.
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>> > > > > > >>> Just wanted to make sure it didn't get lost
> > > here.
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>> > > > > > >>> --Matt
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM PRATEEK
> > GAUR <
> > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > >> >> >>> > > > > > >>> wrote:
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>> > > > > > >>> > Hi all,
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > I'd like to share a status update on the
> > ALP
> > > > > >> encoding
> > > > > >> >> >>> effort
> > > > > >> >> >>> > > and
> > > > > >> >> >>> > > > > get
> > > > > >> >> >>> > > > > > a
> > > > > >> >> >>> > > > > > >>> feel
> > > > > >> >> >>> > > > > > >>> > from the community before starting a
> formal
> > > > vote.
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > We now have the specification plus
> > > > > implementations
> > > > > >> in
> > > > > >> >> >>> both
> > > > > >> >> >>> > > > > languages:
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> >     - Spec:
> > >  apache/parquet-format#557 —
> > > > > >> GH-533
> > > > > >> >> >>> Add
> > > > > >> >> >>> > ALP
> > > > > >> >> >>> > > > > > encoding
> > > > > >> >> >>> > > > > > >>> > specification
> > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):  apache/arrow#48345 —
> > > > GH-48701
> > > > > >> >> >>> > > [C++][Parquet]
> > > > > >> >> >>> > > > > Add
> > > > > >> >> >>> > > > > > >>> ALPpd
> > > > > >> >> >>> > > > > > >>> > encoding
> > > > > >> >> >>> > > > > > >>> >     - Java:
> >  apache/parquet-java#3397
> > > —
> > > > > >> Parquet
> > > > > >> >> >>> Java
> > > > > >> >> >>> > ALP
> > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > Current state:
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> >     - The C++ implementation has been
> > through
> > > > 3-4
> > > > > >> >> rounds
> > > > > >> >> >>> of
> > > > > >> >> >>> > > > review.
> > > > > >> >> >>> > > > > > >>> >     - The Java implementation has been
> > > tracking
> > > > > >> well
> > > > > >> >> and
> > > > > >> >> >>> has
> > > > > >> >> >>> > > had
> > > > > >> >> >>> > > > > > >>> initial
> > > > > >> >> >>> > > > > > >>> >       reviews from contributors, with no
> > > major
> > > > > >> >> remaining
> > > > > >> >> >>> > > issues.
> > > > > >> >> >>> > > > > > >>> >     - Cross-language compatibility tests
> > are
> > > > > >> passing:
> > > > > >> >> the
> > > > > >> >> >>> > Arrow
> > > > > >> >> >>> > > > C++
> > > > > >> >> >>> > > > > > >>> decoder
> > > > > >> >> >>> > > > > > >>> >       reads Java-written data bit-exactly
> > > > across
> > > > > >> >> ~1.56M
> > > > > >> >> >>> > values
> > > > > >> >> >>> > > > and
> > > > > >> >> >>> > > > > 18
> > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1 and V2 pages,
> > > > > multiple
> > > > > >> >> vector
> > > > > >> >> >>> > > sizes,
> > > > > >> >> >>> > > > > and
> > > > > >> >> >>> > > > > > >>> > several
> > > > > >> >> >>> > > > > > >>> >       real datasets — zero mismatches.
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we will be
> adding
> > > > > >> coverage
> > > > > >> >> for
> > > > > >> >> >>> > > extreme
> > > > > >> >> >>> > > > > > values
> > > > > >> >> >>> > > > > > >>> > (those requiring
> > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is applied) before
> we
> > > > > close a
> > > > > >> >> vote.
> > > > > >> >> >>> > We'll
> > > > > >> >> >>> > > > aim
> > > > > >> >> >>> > > > > > to
> > > > > >> >> >>> > > > > > >>> get
> > > > > >> >> >>> > > > > > >>> > that
> > > > > >> >> >>> > > > > > >>> >  done in parallel.
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > Plan: unless there are objections, I
> intend
> > > to
> > > > > >> start a
> > > > > >> >> >>> vote
> > > > > >> >> >>> > at
> > > > > >> >> >>> > > > the
> > > > > >> >> >>> > > > > > end
> > > > > >> >> >>> > > > > > >>> of
> > > > > >> >> >>> > > > > > >>> > this week/early
> > > > > >> >> >>> > > > > > >>> > next week.
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > Thanks
> > > > > >> >> >>> > > > > > >>> > Prateek
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM PRATEEK
> > GAUR <
> > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > >> >> >>> > > > > > >>> wrote:
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>> > > Hi Team,
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some updates on
> > ALP.
> > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4 rounds of
> > review
> > > > for
> > > > > >> the
> > > > > >> >> c++
> > > > > >> >> >>> PR :
> > > > > >> >> >>> > > > > > >>> > >
> > https://github.com/apache/arrow/pull/48345
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> > > For the Java implementation Vinoo has
> > been
> > > > > >> working
> > > > > >> >> on
> > > > > >> >> >>> > > following
> > > > > >> >> >>> > > > > PR
> > > > > >> >> >>> > > > > > :
> > > > > >> >> >>> > > > > > >>> > >
> > > > > https://github.com/apache/parquet-java/pull/3397
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> > > Best
> > > > > >> >> >>> > > > > > >>> > > Prateek
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at 1:50 PM Micah
> > > > Kornfield
> > > > > <
> > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> > > > > >> >> >>> > > > > > >>> > > wrote:
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> already
> > > > asked,
> > > > > >> but
> > > > > >> >> >>> should
> > > > > >> >> >>> > we
> > > > > >> >> >>> > > > > care
> > > > > >> >> >>> > > > > > >>> about
> > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT + ALP be
> > more
> > > > > >> >> efficient
> > > > > >> >> >>> than
> > > > > >> >> >>> > > > > FLOAT16
> > > > > >> >> >>> > > > > > +
> > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for example?
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we could defer it
> > for
> > > > the
> > > > > >> >> >>> following
> > > > > >> >> >>> > > > reasons:
> > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there are a lot of
> > easy
> > > > > >> >> reference
> > > > > >> >> >>> > > datasets
> > > > > >> >> >>> > > > to
> > > > > >> >> >>> > > > > > >>> test
> > > > > >> >> >>> > > > > > >>> > its
> > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does look like
> there
> > > > might
> > > > > be
> > > > > >> >> one
> > > > > >> >> >>> or
> > > > > >> >> >>> > two
> > > > > >> >> >>> > > on
> > > > > >> >> >>> > > > > > >>> > huggingface
> > > > > >> >> >>> > > > > > >>> > >> (e.g.
> > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> > > > > >> >> >>> ).
> > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that float 16 was
> > > more
> > > > > >> likely
> > > > > >> >> >>> used
> > > > > >> >> >>> > for
> > > > > >> >> >>> > > > > values
> > > > > >> >> >>> > > > > > >>> that
> > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce to decimal
> > > > values.
> > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an extension
> > > later
> > > > if
> > > > > >> >> needed.
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >> Cheers,
> > > > > >> >> >>> > > > > > >>> > >> Micah
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at 1:40 PM Antoine
> > > > Pitrou
> > > > > <
> > > > > >> >> >>> > > > > antoine@python.org
> > > > > >> >> >>> > > > > > >
> > > > > >> >> >>> > > > > > >>> > wrote:
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > Hello,
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> already
> > > > asked,
> > > > > >> but
> > > > > >> >> >>> should
> > > > > >> >> >>> > we
> > > > > >> >> >>> > > > > care
> > > > > >> >> >>> > > > > > >>> about
> > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT + ALP be
> > more
> > > > > >> >> efficient
> > > > > >> >> >>> than
> > > > > >> >> >>> > > > > FLOAT16
> > > > > >> >> >>> > > > > > +
> > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for example?
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > Regards
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10, PRATEEK GAUR
> a
> > > > écrit
> > > > > :
> > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah for review
> > > > > feedback
> > > > > >> on
> > > > > >> >> >>> the two
> > > > > >> >> >>> > > > PR's
> > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> https://github.com/apache/arrow/pull/48345/changes
> > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format repo)
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> https://github.com/apache/parquet-format/pull/557
> > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all (unless I
> > missed
> > > > > >> >> something)
> > > > > >> >> >>> > > comments
> > > > > >> >> >>> > > > on
> > > > > >> >> >>> > > > > > >>> the two
> > > > > >> >> >>> > > > > > >>> > >> > PR's.
> > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > >> >> >>> > > > > > >>> > >> > > Best
> > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at 1:08 PM
> > > PRATEEK
> > > > > >> GAUR <
> > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> > > > > >> >> >>> > > > > > >>> > >> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and Micah.
> > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of feedback on at
> > least
> > > > the
> > > > > >> >> >>> > > implementations`
> > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have already
> started
> > > > > >> addressing
> > > > > >> >> the
> > > > > >> >> >>> > > > > feedback, I
> > > > > >> >> >>> > > > > > >>> > should
> > > > > >> >> >>> > > > > > >>> > >> be
> > > > > >> >> >>> > > > > > >>> > >> > >> done with that Monday/Tuesday.
> > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has been making
> > > good
> > > > > >> >> progress
> > > > > >> >> >>> on
> > > > > >> >> >>> > the
> > > > > >> >> >>> > > > Java
> > > > > >> >> >>> > > > > > >>> > >> > implementation.
> > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > >> >> >>> > > > > > >>> > >> > >> Best
> > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026 at 12:55 PM
> > > Andrew
> > > > > >> Lamb <
> > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for the
> > > > clarification
> > > > > >> -- I
> > > > > >> >> >>> will
> > > > > >> >> >>> > try
> > > > > >> >> >>> > > > and
> > > > > >> >> >>> > > > > > look
> > > > > >> >> >>> > > > > > >>> > into
> > > > > >> >> >>> > > > > > >>> > >> the
> > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> > implementation[1]
> > > in
> > > > > >> this
> > > > > >> >> next
> > > > > >> >> >>> > week
> > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
> > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026 at 12:01 PM
> > > Micah
> > > > > >> >> >>> Kornfield <
> > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a fair amount
> of
> > > > > >> feedback
> > > > > >> >> on
> > > > > >> >> >>> at
> > > > > >> >> >>> > > least
> > > > > >> >> >>> > > > > the
> > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations, typically I
> > think
> > > > > we've
> > > > > >> >> waited
> > > > > >> >> >>> > till
> > > > > >> >> >>> > > > they
> > > > > >> >> >>> > > > > > are
> > > > > >> >> >>> > > > > > >>> > >> close to
> > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a final vote.
> > > > > >> Otherwise I
> > > > > >> >> >>> agree
> > > > > >> >> >>> > we
> > > > > >> >> >>> > > > are
> > > > > >> >> >>> > > > > > very
> > > > > >> >> >>> > > > > > >>> > >> close.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April 25, 2026,
> > Andrew
> > > > > Lamb
> > > > > >> <
> > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> > >> > wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this content it
> > looks
> > > > to
> > > > > me
> > > > > >> >> like
> > > > > >> >> >>> we
> > > > > >> >> >>> > are
> > > > > >> >> >>> > > > > ready
> > > > > >> >> >>> > > > > > >>> to
> > > > > >> >> >>> > > > > > >>> > >> start a
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly accept ALP
> > into
> > > > > >> Parquet
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know of a reason
> we
> > > > should
> > > > > >> >> >>> postpone it
> > > > > >> >> >>> > > for
> > > > > >> >> >>> > > > > > >>> longer?
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone needs some
> more
> > > time
> > > > > to
> > > > > >> >> >>> review?
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22, 2026 at
> 1:00 PM
> > > > > PRATEEK
> > > > > >> >> GAUR <
> > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is doing well.
> I
> > > got
> > > > a
> > > > > >> >> chance
> > > > > >> >> >>> to
> > > > > >> >> >>> > work
> > > > > >> >> >>> > > > > > >>> through all
> > > > > >> >> >>> > > > > > >>> > >> the
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback and update
> > the
> > > > > spec
> > > > > >> >> doc.
> > > > > >> >> >>> Here
> > > > > >> >> >>> > > are
> > > > > >> >> >>> > > > > the
> > > > > >> >> >>> > > > > > >>> new
> > > > > >> >> >>> > > > > > >>> > >> > artifacts
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > >
> > > > > >> >> >>> > > >
> > > > > >> >> >>> > >
> > > > > >> >> >>> >
> > > > > >> >> >>>
> > > > > >> >>
> > > > > >>
> > > > >
> > > >
> > >
> >
> https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-3fPtD_aWt/edit
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document in parquet
> > > format
> > > > > >> repo :
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > https://github.com/apache/parquet-format/pull/557
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp implementation in
> arrow
> > > c++
> > > > > >> repo :
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > https://github.com/apache/arrow/pull/48345/changes
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp implementation in
> > > > parquet-java
> > > > > >> >> repo :
> > > > > >> >> >>> Work
> > > > > >> >> >>> > > for
> > > > > >> >> >>> > > > > > >>> Vinoo and
> > > > > >> >> >>> > > > > > >>> > >> > Julien
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > https://github.com/apache/parquet-java/pull/3397
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test and
> > benchmarking
> > > > > >> >> artifacts in
> > > > > >> >> >>> > > > > > >>> parquet-testing
> > > > > >> >> >>> > > > > > >>> > >> repo :
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > https://github.com/apache/parquet-testing/pull/100
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav just
> submitted
> > > an
> > > > in
> > > > > >> >> >>> progress
> > > > > >> >> >>> > > > > > >>> implementation
> > > > > >> >> >>> > > > > > >>> > in
> > > > > >> >> >>> > > > > > >>> > >> Go.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> https://github.com/apache/arrow-go/pull/704
> > > > > >> >> >>> > (I
> > > > > >> >> >>> > > > > > haven't
> > > > > >> >> >>> > > > > > >>> > >> started
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     looking at it yet)
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Rust : I remember
> Andrew
> > > > > >> mentioned
> > > > > >> >> that
> > > > > >> >> >>> > this
> > > > > >> >> >>> > > > work
> > > > > >> >> >>> > > > > > is
> > > > > >> >> >>> > > > > > >>> also
> > > > > >> >> >>> > > > > > >>> > >> in
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     progress (So 4
> languages!)
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Arrow C++ implementation *
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> The PR is out and was also
> used
> > > by
> > > > > >> >> Antoine to
> > > > > >> >> >>> > > report
> > > > > >> >> >>> > > > > the
> > > > > >> >> >>> > > > > > >>> > numbers
> > > > > >> >> >>> > > > > > >>> > >> as
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> reported here. Micah and
> > > Konstantin
> > > > > >> have
> > > > > >> >> >>> given 1
> > > > > >> >> >>> > > > round
> > > > > >> >> >>> > > > > of
> > > > > >> >> >>> > > > > > >>> > >> feedback
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> and I'm addressing them
> today.
> > > > Please
> > > > > >> note
> > > > > >> >> >>> that
> > > > > >> >> >>> > the
> > > > > >> >> >>> > > > > > default
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> optimization flag for
> compiling
> > > is
> > > > O2
> > > > > >> and
> > > > > >> >> not
> > > > > >> >> >>> > Q3. I
> > > > > >> >> >>> > > > got
> > > > > >> >> >>> > > > > > >>> around
> > > > > >> >> >>> > > > > > >>> > >> 70%
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> performance improvement in
> the
> > > > > decoding
> > > > > >> >> speed
> > > > > >> >> >>> > when
> > > > > >> >> >>> > > > > using
> > > > > >> >> >>> > > > > > >>> the O3
> > > > > >> >> >>> > > > > > >>> > >> > flag.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Parqet-MR Java
> implementation
> > > > > (working
> > > > > >> >> with
> > > > > >> >> >>> > Vinoo
> > > > > >> >> >>> > > > and
> > > > > >> >> >>> > > > > > >>> Julien)
> > > > > >> >> >>> > > > > > >>> > >> and
> > > > > >> >> >>> > > > > > >>> > >> > **Cross
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Language testing*
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     Let me know if you have
> any
> > > > > >> questions
> > > > > >> >> or
> > > > > >> >> >>> > > > feedback.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Now pasting some performance
> > > > numbers
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    Table 1: C++ ALP Double
> > > Decode —
> > > > > >> >> Spotify
> > > > > >> >> >>> > Columns
> > > > > >> >> >>> > > > > > >>> (Graviton
> > > > > >> >> >>> > > > > > >>> > 3,
> > > > > >> >> >>> > > > > > >>> > >> ARM
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Neoverse V1)
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>>
> > ┌──────────────────┬──────────────┬──────────────┬─────────┐
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ Column           │  -O2
> > > (MB/s)
> > > > > │
> > > > > >> >> -O3
> > > > > >> >> >>> > > (MB/s)  │
> > > > > >> >> >>> > > > > > >>> Speedup │
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>>
> > ├──────────────────┼──────────────┼──────────────┼─────────┤
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ valence          │
> >  3,155
> > > > > │
> > > > > >> >> >>>  5,523
> > > > > >> >> >>> > >   │
> > > > > >> >> >>> > > > > > >>> 1.75x  │
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ danceability     │
> >  3,233
> > > > > │
> > > > > >> >> >>>  5,685
> > > > > >> >> >>> > >   │
> > > > > >> >> >>> > > > > > >>> 1.76x  │
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ energy           │
> >  3,197
> > > > > │
> > > > > >> >> >>>  5,652
> > > > > >> >> >>> > >   │
> > > > > >> >> >>> > > > > > >>> 1.77x  │
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ loudness         │
> >  3,186
> > > > > │
> > > > > >> >> >>>  5,473
> > > > > >> >> >>> > >   │
> > > > > >> >> >>> > > > > > >>> 1.72x  │
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>>
> > └──────────────────┴──────────────┴──────────────┴─────────┘
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> On Wed, Feb 25, 2026 at
> 9:49 AM
> > > > > PRATEEK
> > > > > >> >> GAUR
> > > > > >> >> >>> <
> > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Micah Kornfield <
> > > > > >> emkornfield@gmail.com>
> > > > > >> >> :
> > > > > >> >> >>> Got
> > > > > >> >> >>> > > it.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Andrew Lamb <
> > > > > andrewlamb11@gmail.com>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Do you think it would be
> good
> > > to
> > > > > >> start
> > > > > >> >> >>> moving
> > > > > >> >> >>> > the
> > > > > >> >> >>> > > > > spec
> > > > > >> >> >>> > > > > > >>> > >> development
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> into
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> markdown format, in
> > preparation
> > > > for
> > > > > >> >> >>> finalizing
> > > > > >> >> >>> > > it?
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Yes I'll update the numbers
> > for
> > > > some
> > > > > >> of
> > > > > >> >> the
> > > > > >> >> >>> > > > examples I
> > > > > >> >> >>> > > > > > >>> have in
> > > > > >> >> >>> > > > > > >>> > >> the
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> spec based
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> on the updated header size.
> > Then
> > > > we
> > > > > >> >> should
> > > > > >> >> >>> be
> > > > > >> >> >>> > good
> > > > > >> >> >>> > > > to
> > > > > >> >> >>> > > > > go
> > > > > >> >> >>> > > > > > >>> for
> > > > > >> >> >>> > > > > > >>> > the
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> markdown format.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Thanks everyone!
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Andrew
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> On Tue, Feb 17, 2026 at
> > 7:28 PM
> > > > > >> PRATEEK
> > > > > >> >> >>> GAUR <
> > > > > >> >> >>> > > > > > >>> > >> prtkgaur@gmail.com>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Hi team,
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 1) Andrew
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for working
> on
> > > test
> > > > > >> files.
> > > > > >> >> >>> My PR
> > > > > >> >> >>> > > did
> > > > > >> >> >>> > > > > add
> > > > > >> >> >>> > > > > > >>> all
> > > > > >> >> >>> > > > > > >>> > the
> > > > > >> >> >>> > > > > > >>> > >> > test
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> files I
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     used to benchmark on
> > > > datasets.
> > > > > >> >> Maybe
> > > > > >> >> >>> we
> > > > > >> >> >>> > can
> > > > > >> >> >>> > > > club
> > > > > >> >> >>> > > > > > it
> > > > > >> >> >>> > > > > > >>> > >> together.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> WIll also
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> aid
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     cross language testing
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     -  Kosta Tarasov
> working
> > > on
> > > > > Rust
> > > > > >> >> >>> > > > implementation.
> > > > > >> >> >>> > > > > > >>> This is
> > > > > >> >> >>> > > > > > >>> > >> > great.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Thanks
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 2) Antoine
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks a lot for
> > > reporting
> > > > > the
> > > > > >> >> >>> numbers
> > > > > >> >> >>> > on
> > > > > >> >> >>> > > > AMD.
> > > > > >> >> >>> > > > > > >>> Looks
> > > > > >> >> >>> > > > > > >>> > >> like
> > > > > >> >> >>> > > > > > >>> > >> > you
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> are
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     getting 8X the
> decoding
> > > > > >> >> performance of
> > > > > >> >> >>> > BSS.
> > > > > >> >> >>> > > > This
> > > > > >> >> >>> > > > > > is
> > > > > >> >> >>> > > > > > >>> > >> > amazing!!.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > acknowledging
> > > > the
> > > > > >> >> >>> sampling
> > > > > >> >> >>> > > > design.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - I agree with you on
> > > > > >> Fastlanes. In
> > > > > >> >> >>> some
> > > > > >> >> >>> > > crude
> > > > > >> >> >>> > > > > > >>> > >> experiments I
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> didn't get
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     a good perf benefit
> from
> > > it
> > > > on
> > > > > >> >> >>> Graviton3
> > > > > >> >> >>> > > (but
> > > > > >> >> >>> > > > > > maybe
> > > > > >> >> >>> > > > > > >>> > there
> > > > > >> >> >>> > > > > > >>> > >> was
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> something
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     wrong with my
> > > > implementation).
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Locking the 16bit
> > > > exception
> > > > > >> >> >>> encoding for
> > > > > >> >> >>> > > the
> > > > > >> >> >>> > > > > > spec
> > > > > >> >> >>> > > > > > >>> in
> > > > > >> >> >>> > > > > > >>> > >> this
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> case.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Awesome I think we
> > have
> > > > > solved
> > > > > >> >> for
> > > > > >> >> >>> all
> > > > > >> >> >>> > > open
> > > > > >> >> >>> > > > > > >>> questions
> > > > > >> >> >>> > > > > > >>> > >> minus
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     version byte :). (will
> > get
> > > > > back
> > > > > >> on
> > > > > >> >> >>> this
> > > > > >> >> >>> > > soon)
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 3) Micah
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - FastLanes : The
> > current
> > > > spec
> > > > > >> does
> > > > > >> >> >>> allow
> > > > > >> >> >>> > > for
> > > > > >> >> >>> > > > > > using
> > > > > >> >> >>> > > > > > >>> > >> FastLane
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> with the
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     configurable enum
> value
> > > for
> > > > > >> >> layout. We
> > > > > >> >> >>> > > should
> > > > > >> >> >>> > > > be
> > > > > >> >> >>> > > > > > >>> able to
> > > > > >> >> >>> > > > > > >>> > >> > inject
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> any
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> layout
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     in the current design.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Working on resolving all
> > > > remaining
> > > > > >> open
> > > > > >> >> >>> > comments
> > > > > >> >> >>> > > > on
> > > > > >> >> >>> > > > > > the
> > > > > >> >> >>> > > > > > >>> spec
> > > > > >> >> >>> > > > > > >>> > >> this
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> week.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10, 2026 at
> > > 3:37 AM
> > > > > >> Steve
> > > > > >> >> >>> > Loughran <
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> stevel@cloudera.com>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb 2026 at
> > 18:12,
> > > > > Micah
> > > > > >> >> >>> Kornfield
> > > > > >> >> >>> > <
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> emkornfield@gmail.com>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like the actual
> > > issue
> > > > > >> >> >>> described for
> > > > > >> >> >>> > > ORC
> > > > > >> >> >>> > > > > in
> > > > > >> >> >>> > > > > > >>> the
> > > > > >> >> >>> > > > > > >>> > >> paper
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
> sub-encodings
> > > in
> > > > a
> > > > > >> >> batch.
> > > > > >> >> >>> This
> > > > > >> >> >>> > > is
> > > > > >> >> >>> > > > > > >>> different
> > > > > >> >> >>> > > > > > >>> > >> then
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here where
> there
> > is
> > > > > still
> > > > > >> >> fixed
> > > > > >> >> >>> > > > encoding
> > > > > >> >> >>> > > > > > per
> > > > > >> >> >>> > > > > > >>> page
> > > > > >> >> >>> > > > > > >>> > >> in
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given reasonably sized
> > > pages I
> > > > > >> don't
> > > > > >> >> >>> think
> > > > > >> >> >>> > > > branch
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction should
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for new
> > encodings.
> > > > I
> > > > > >> agree
> > > > > >> >> >>> that
> > > > > >> >> >>> > we
> > > > > >> >> >>> > > > > should
> > > > > >> >> >>> > > > > > >>> be
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for adding new
> > > > > encodings.
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >> >
> > > > > >> >> >>> > > > > > >>> > >>
> > > > > >> >> >>> > > > > > >>> > >
> > > > > >> >> >>> > > > > > >>> >
> > > > > >> >> >>> > > > > > >>>
> > > > > >> >> >>> > > > > > >>
> > > > > >> >> >>> > > > > >
> > > > > >> >> >>> > > > >
> > > > > >> >> >>> > > >
> > > > > >> >> >>> > >
> > > > > >> >> >>> >
> > > > > >> >> >>>
> > > > > >> >> >>
> > > > > >> >>
> > > > > >> >
> > > > > >>
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [Parquet] ALP Encoding for Floating point data

[Antoine Pitrou <an...@python.org>]

Hi Prateek!

Le 13/11/2026 à 07:44, PRATEEK GAUR a écrit :
> 
>> I would be curious if this has been experimented with already
>> (pseudo-random sampling).
> 
> Thanks, Antoine. Your comment prompted me to revisit the Arrow C++ sampler
> and experiment
> with a simpler approach using fixed-seed pseudo-random sampling.
> - Pick evenly spaced value vectors across the page. This ensures values are
> picked from different
>    parts of the input.
> - From each vector, pick 32 (fixed) pseudo-random values using a fixed seed
> so the result remains
>    deterministic. This ensures a statistically meaningful sample while
> further reducing the sample
>    size (to reduce CPU compute).
> 
> Trying this on the dataset I didn't see any meaningful regression in
> compression ratio or
> decoding speed. So we can simplify the implementation.

Thank you, but my proposal goes a bit further: how about dropping the 
"evenly spaced value vectors" and instead just sample the desired number 
of values (for example 256) from the page?

Some PRNGs are extremely fast and I doubt the cost of sampling would be 
significant compared to the actual cost of deriving ALP parameters from 
the samples?

Regards

Antoine.

Re: [Parquet] ALP Encoding for Floating point data

[Antoine Pitrou <an...@python.org>]

Le 12/11/2026 à 13:42, Gang Wu a écrit :
> 
> I'm trying to improve the ALP implementations on the Parquet C++ side:
> https://github.com/apache/arrow/pull/55449. So I'm really interested
> if you have any document on performance comparison among different
> implementations.

When reviewing this PR, the question came up of why use such weird and 
ad-hoc sampling schemes instead of actual pseudo-random sampling using a 
good and fast PRNG.

I would be curious if this has been experimented with already 
(pseudo-random sampling).

Regards

Antoine.




> 
> Thanks!
> Gang
> 
> On Thu, Nov 12, 2026 at 6:50 PM Gunnar Morling via dev <
> dev@parquet.apache.org> wrote:
> 
>> Hey all,
>>
>> We've added ALP encoding and decoding support to Hardwood too [1], [2].
>> Interop with parquet-java's implementation looks good: Hardwood decodes
>> pages written by parquet-java's ALP writer bit-exactly and vice versa.
>>
>> Perhaps interesting: on the encoder side, we build the preset of a column
>> chunk from eight sample vectors distributed across the entire chunk (easy
>> in our case, as Hardwood's writer buffers whole chunks), whereas, IIUC,
>> parquet-java only samples within the first ~110K values of a chunk.
>> Depending on the data distribution, this can yield a more efficient
>> encoding, for instance when a high-cardinality column changes character
>> midway, e.g. moving from two to four decimal places (about 2.8× smaller in
>> a synthetic test with 1M doubles).
>>
>> Best,
>>
>> --Gunnar

Re: [Parquet] ALP Encoding for Floating point data

[PRATEEK GAUR <pr...@gmail.com>]

Hi Gunnar, Gang, Antoine,

> Interop with parquet-java's implementation looks good: Hardwood decodes
> pages written by parquet-java's ALP writer bit-exactly and vice versa.

Thanks, Gunnar. That is great to hear.

> on the encoder side, we build the preset of a column chunk from eight
> sample vectors distributed across the entire chunk [...] whereas, IIUC,
> parquet-java only samples within the first ~110K values of a chunk.

Yes that's right about parquet-java: its writer encodes one vector at a
time and fixes the preset
after sampling roughly the first 110K values.

Since Hardwood buffers the entire column chunk, distributing eight sample
vectors across it
makes sense. Arrow C++ instead draws samples from across each data page and
builds a fresh
preset for every page. This lets it adapt between pages, at the cost of
repeating preset
selection.

> I would be curious if this has been experimented with already
> (pseudo-random sampling).

Thanks, Antoine. Your comment prompted me to revisit the Arrow C++ sampler
and experiment
with a simpler approach using fixed-seed pseudo-random sampling.
- Pick evenly spaced value vectors across the page. This ensures values are
picked from different
  parts of the input.
- From each vector, pick 32 (fixed) pseudo-random values using a fixed seed
so the result remains
  deterministic. This ensures a statistically meaningful sample while
further reducing the sample
  size (to reduce CPU compute).

Trying this on the dataset I didn't see any meaningful regression in
compression ratio or
decoding speed. So we can simplify the implementation.

> I'm trying to improve the ALP implementations on the Parquet C++ side:
> https://github.com/apache/arrow/pull/55449.

Thanks Gang, I haven't had a chance to look at your PR yet, but I'll get to
it soon. Since it
touches the same sampling code, I'm happy to compare notes once I've read
it.

> Hardwood decodes 5–6× faster than parquet-java
Thanks for this data point. Is fusing the one helping with speed up?
cc @Vinoo Ganesh <vi...@gmail.com> .

> encodes a page 2–4× faster once both presets exist.
That makes sense. As you noted, Hardwood evaluates the preset pairs using a
smaller sample,
while parquet-java evaluates all 1,024 values in each vector. That reduces
encoding work even
after the preset has been built.

Best,
Prateek

On Thu, Nov 12, 2026 at 9:42 AM Gunnar Morling via dev <
dev@parquet.apache.org> wrote:

> Hey Gang,
>
> Yeah, agreed, I think it's more similar in the sense that we take the
> samples for the preset from across the whole chunk instead of only from its
> first segment. AFAIK, DuckDB also resamples and then uses dedicated presets
> for specific segments, which can yield even better results but also is more
> costly.
>
> As for a perf comparison, I have a quick informal (LLM-coded)
> microbenchmark of parquet-java's and Hardwood's ALP decoders and encoders
> in this draft PR [1]. In that benchmark, in a Docker container on my
> laptop, Hardwood decodes 5–6× faster than parquet-java and encodes a page
> 2–4× faster once both presets exist (pages purely in memory, no
> compression, etc.). Based on some quick profiling, IIUC, it mostly comes
> down to bit unpacking on decode (generic 8-at-a-time BytePacker plus a
> separate decode pass vs. one fused loop with a single 8-byte load per
> value), and on encode to parquet-java evaluating each preset pair on the
> full vector rather than a sample.
>
> Numbers may look different elsewhere, so I'd be curious to learn about your
> results, also if there's something to do better in the benchmark itself,
> etc.
>
> Best,
>
> --Gunnar
>
> [1] https://github.com/hardwood-hq/hardwood/pull/1775
>
>
> On Thu, 12 Nov 2026 at 13:42, Gang Wu <us...@gmail.com> wrote:
>
> > Thanks Gunnar for sharing this!
> >
> > I think the encoder approach used by Hardwood looks more similar to the
> ALP
> > paper where all 102,400 values are buffered to decide best presets and
> then
> > encode every vector based on those presets.
> >
> > I'm trying to improve the ALP implementations on the Parquet C++ side:
> > https://github.com/apache/arrow/pull/55449. So I'm really interested
> > if you have any document on performance comparison among different
> > implementations.
> >
> > Thanks!
> > Gang
> >
> > On Thu, Nov 12, 2026 at 6:50 PM Gunnar Morling via dev <
> > dev@parquet.apache.org> wrote:
> >
> >> Hey all,
> >>
> >> We've added ALP encoding and decoding support to Hardwood too [1], [2].
> >> Interop with parquet-java's implementation looks good: Hardwood decodes
> >> pages written by parquet-java's ALP writer bit-exactly and vice versa.
> >>
> >> Perhaps interesting: on the encoder side, we build the preset of a
> column
> >> chunk from eight sample vectors distributed across the entire chunk
> (easy
> >> in our case, as Hardwood's writer buffers whole chunks), whereas, IIUC,
> >> parquet-java only samples within the first ~110K values of a chunk.
> >> Depending on the data distribution, this can yield a more efficient
> >> encoding, for instance when a high-cardinality column changes character
> >> midway, e.g. moving from two to four decimal places (about 2.8× smaller
> in
> >> a synthetic test with 1M doubles).
> >>
> >> Best,
> >>
> >> --Gunnar
> >>
> >> [1] https://github.com/hardwood-hq/hardwood/pull/1496
> >> [2] https://github.com/hardwood-hq/hardwood/pull/1769
> >>
> >>
> >> On Thu, 12 Nov 2026 at 07:01, PRATEEK GAUR <pr...@gmail.com> wrote:
> >>
> >> > Thanks everyone!
> >> >
> >> > On Mon, Nov 9, 2026 at 11:58 AM Vinoo Ganesh <vi...@gmail.com>
> >> > wrote:
> >> >
> >> > > Thanks everyone!
> >> > >
> >> > > Thanks,
> >> > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> >> > >
> >> > > <Vi...@gmail.com>
> >> > >
> >> > >
> >> > > On Mon, Nov 9, 2026 at 2:49 PM Andrew Lamb <an...@gmail.com>
> >> > wrote:
> >> > >
> >> > > > The Java implementation was just merged[1]!
> >> > > >
> >> > > > Thank you Gang, Vinoo, Prateek and everyone who helped push that
> one
> >> > > along
> >> > > >
> >> > > > Andrew
> >> > > >
> >> > > > [1]:
> >> > https://github.com/apache/parquet-java/pull/3397#event-35545451335
> >> > > >
> >> > > > On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <prtkgaur@gmail.com
> >
> >> > > wrote:
> >> > > >
> >> > > > > Hi team,
> >> > > > >
> >> > > > > Quick update re: the C++ implementation.
> >> > > > > Thanks to all the reviewers, we merged the C++ implementation
> >> today.
> >> > > > > There are a few follow-up items that I'll address in a
> subsequent
> >> PR.
> >> > > > >
> >> > > > > Thanks
> >> > > > > Prateek
> >> > > > >
> >> > > > > On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <
> >> vinoo.ganesh@gmail.com
> >> > >
> >> > > > > wrote:
> >> > > > >
> >> > > > > > Quick update re: the Java impl. Thanks for the feedback, on
> >> > > > > > https://github.com/apache/parquet-java/pull/3397, Russel! I
> >> pulled
> >> > > > > > https://github.com/apache/parquet-java/pull/3791 into its own
> >> PR
> >> > > > (thanks
> >> > > > > > for the quick approval too, Gang). Assuming no objections, I
> >> think
> >> > we
> >> > > > can
> >> > > > > > merge #3791, and then go ahead of #3397.
> >> > > > > >
> >> > > > > > Thanks,
> >> > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> >> > > > > >
> >> > > > > > <Vi...@gmail.com>
> >> > > > > >
> >> > > > > >
> >> > > > > > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <
> >> prtkgaur@gmail.com>
> >> > > > wrote:
> >> > > > > >
> >> > > > > > > [Rust] Awesome thanks Andrew, Kostas and Devin.
> >> > > > > > > [Java] Thanks Gang for the feedback on Java PR.
> >> > > > > > > [C++] Thanks Gang for another round of feedback on the C++
> >> one.
> >> > > > > > > [Go] Arnav and I will be working on the golang impl this
> week.
> >> > > > > > >
> >> > > > > > > This is great progress all around.
> >> > > > > > >
> >> > > > > > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <
> >> > > vinoo.ganesh@gmail.com>
> >> > > > > > > wrote:
> >> > > > > > >
> >> > > > > > > > Thanks all - I'm addressing Gang's comments on
> >> > > > > > > > https://github.com/apache/parquet-java/pull/3397 now, so
> >> > > hopefully
> >> > > > > > well
> >> > > > > > > > also be in a good state for merging the java
> implementation
> >> > soon.
> >> > > > > > > >
> >> > > > > > > > Thanks,
> >> > > > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> >> > > > > > > >
> >> > > > > > > > <Vi...@gmail.com>
> >> > > > > > > >
> >> > > > > > > >
> >> > > > > > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <
> >> > > andrewlamb11@gmail.com
> >> > > > >
> >> > > > > > > wrote:
> >> > > > > > > >
> >> > > > > > > > > We just merged the Rust implementation[1] from Kosta and
> >> > Devan.
> >> > > > > With
> >> > > > > > > the
> >> > > > > > > > > imminent release of Parquet Format 2.14.0 I think we'll
> be
> >> > well
> >> > > > on
> >> > > > > > our
> >> > > > > > > > way.
> >> > > > > > > > >
> >> > > > > > > > > Thanks again for pushing this along,
> >> > > > > > > > > Andrew
> >> > > > > > > > >
> >> > > > > > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> >> > > > > > > > >
> >> > > > > > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <
> >> > > prtkgaur@gmail.com>
> >> > > > > > > wrote:
> >> > > > > > > > >
> >> > > > > > > > > > Hi team,
> >> > > > > > > > > >
> >> > > > > > > > > > Thanks Micah for multiple rounds of review and thanks
> >> Gang
> >> > > for
> >> > > > > > > taking a
> >> > > > > > > > > > look at the PR and giving feedback. I've addressed all
> >> > > comments
> >> > > > > in
> >> > > > > > > the
> >> > > > > > > > > PR.
> >> > > > > > > > > > Looking forward to the next round of feedback (or
> >> > approval).
> >> > > > > Would
> >> > > > > > > like
> >> > > > > > > > > to
> >> > > > > > > > > > get it in soon.
> >> > > > > > > > > >
> >> > > > > > > > > > https://github.com/apache/arrow/pull/48345/changes
> >> > > > > > > > > >
> >> > > > > > > > > > With this done and after talking to Arnav, I plan to
> >> spend
> >> > > some
> >> > > > > > time
> >> > > > > > > on
> >> > > > > > > > > the
> >> > > > > > > > > > ALP implementation in the arrow-go repository helping
> >> > spread
> >> > > > the
> >> > > > > > > > support
> >> > > > > > > > > to
> >> > > > > > > > > > more languages.
> >> > > > > > > > > >
> >> > > > > > > > > > Best
> >> > > > > > > > > > Prateek
> >> > > > > > > > > >
> >> > > > > > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <
> >> > > > prtkgaur@gmail.com
> >> > > > > >
> >> > > > > > > > wrote:
> >> > > > > > > > > >
> >> > > > > > > > > > > Thanks Divjot for bringing it up.
> >> > > > > > > > > > >
> >> > > > > > > > > > > I was under the same impression as Russell and
> Andrew
> >> > that
> >> > > > we'd
> >> > > > > > > have
> >> > > > > > > > it
> >> > > > > > > > > > > flag gated.
> >> > > > > > > > > > > With the new versioning proposal 'preview' might be
> a
> >> > good
> >> > > > tag
> >> > > > > > for
> >> > > > > > > > it.
> >> > > > > > > > > > >
> >> > > > > > > > > > > Best
> >> > > > > > > > > > > Prateek
> >> > > > > > > > > > >
> >> > > > > > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> >> > > > > > > andrewlamb11@gmail.com>
> >> > > > > > > > > > > wrote:
> >> > > > > > > > > > >
> >> > > > > > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1]
> >> > > (using a
> >> > > > > > > comment
> >> > > > > > > > > in
> >> > > > > > > > > > >> the
> >> > > > > > > > > > >> spec section).
> >> > > > > > > > > > >>
> >> > > > > > > > > > >> Russel: That is my understanding as well.
> >> > > > > > > > > > >>
> >> > > > > > > > > > >> Hopefully we are able to formalize the versioning
> >> > process
> >> > > > > > shortly
> >> > > > > > > so
> >> > > > > > > > > we
> >> > > > > > > > > > >> can
> >> > > > > > > > > > >> formalize the notion of "preview"
> >> > > > > > > > > > >>
> >> > > > > > > > > > >> Andrew
> >> > > > > > > > > > >>
> >> > > > > > > > > > >>
> >> > > > > > > > > > >> [1]:
> >> https://github.com/apache/parquet-format/pull/604
> >> > > > > > > > > > >>
> >> > > > > > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> >> > > > > > > > > > >> russell.spitzer@gmail.com>
> >> > > > > > > > > > >> wrote:
> >> > > > > > > > > > >>
> >> > > > > > > > > > >> > I thought we had agreed it would be merged, and
> >> > features
> >> > > > > like
> >> > > > > > > this
> >> > > > > > > > > > would
> >> > > > > > > > > > >> > be feature flag gated. So a V-Old writer could
> >> always
> >> > > opt
> >> > > > in
> >> > > > > > to
> >> > > > > > > > > using
> >> > > > > > > > > > >> this
> >> > > > > > > > > > >> > encoding but that must be a conscious effort if
> you
> >> > are
> >> > > > not
> >> > > > > > > using
> >> > > > > > > > > > VNext
> >> > > > > > > > > > >> of
> >> > > > > > > > > > >> > Parquet. If you are on V-Next the writer can
> >> choose to
> >> > > use
> >> > > > > ALP
> >> > > > > > > > > > whenever
> >> > > > > > > > > > >> it
> >> > > > > > > > > > >> > likes without user intervention.
> >> > > > > > > > > > >> >
> >> > > > > > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via
> >> dev <
> >> > > > > > > > > > >> > dev@parquet.apache.org> wrote:
> >> > > > > > > > > > >> >
> >> > > > > > > > > > >> >> Yes, that’s my understanding as well. However,
> as
> >> you
> >> > > > > noted,
> >> > > > > > > the
> >> > > > > > > > > > >> >> versioning
> >> > > > > > > > > > >> >> discussion is still in early stages and hasn’t
> >> > > prescribed
> >> > > > > > > > concrete
> >> > > > > > > > > > >> >> mechanisms yet. If ALP goes into parquet-format
> >> > 2.14.0,
> >> > > > > > there’s
> >> > > > > > > > no
> >> > > > > > > > > > >> >> indication that it’s in preview or that writers
> >> > > shouldn’t
> >> > > > > use
> >> > > > > > > it
> >> > > > > > > > by
> >> > > > > > > > > > >> >> default
> >> > > > > > > > > > >> >> yet. Given that we’ve held off on merging other
> >> > > > > incompatible
> >> > > > > > > > > changes
> >> > > > > > > > > > >> (e.g
> >> > > > > > > > > > >> >> removal of path_in_schema) until the versioning
> >> > > > discussion
> >> > > > > > > > closes,
> >> > > > > > > > > my
> >> > > > > > > > > > >> >> preference would be to leave ALP un-merged for
> the
> >> > time
> >> > > > > being
> >> > > > > > > as
> >> > > > > > > > > > well.
> >> > > > > > > > > > >> >>
> >> > > > > > > > > > >> >> — Div
> >> > > > > > > > > > >> >>
> >> > > > > > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> >> > > > > > > > andrewlamb11@gmail.com>
> >> > > > > > > > > > >> wrote:
> >> > > > > > > > > > >> >>
> >> > > > > > > > > > >> >> > After re-reading Julien's Versioning Proposal,
> >> my
> >> > > > > > > understanding
> >> > > > > > > > > is
> >> > > > > > > > > > >> that
> >> > > > > > > > > > >> >> if
> >> > > > > > > > > > >> >> > we adopt that system, we will somehow mark ALP
> >> in
> >> > > > > "Preview"
> >> > > > > > > in
> >> > > > > > > > > > >> >> > parquet-format for release Version 3.
> >> > > > > > > > > > >> >> >
> >> > > > > > > > > > >> >> > The versioning document doesn't seem to
> >> proscribe
> >> > the
> >> > > > > > > > particular
> >> > > > > > > > > > >> method
> >> > > > > > > > > > >> >> > for annotating "preview" features -- I think
> >> > clearly
> >> > > > > > marking
> >> > > > > > > > them
> >> > > > > > > > > > as
> >> > > > > > > > > > >> >> such
> >> > > > > > > > > > >> >> > in parquet.thrift as well as reflecting that
> on
> >> the
> >> > > > > > > > > > >> >> >
> >> > > https://parquet.apache.org/docs/file-format/versions/
> >> > > > > page
> >> > > > > > > > > somehow
> >> > > > > > > > > > >> >> would
> >> > > > > > > > > > >> >> > be adequate.
> >> > > > > > > > > > >> >> >
> >> > > > > > > > > > >> >> > Andrew
> >> > > > > > > > > > >> >> >
> >> > > > > > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> >> > > > > > > > > > andrewlamb11@gmail.com
> >> > > > > > > > > > >> >
> >> > > > > > > > > > >> >> > wrote:
> >> > > > > > > > > > >> >> >
> >> > > > > > > > > > >> >> >> In my mind ALP is in the same position as
> other
> >> > > > > encodings
> >> > > > > > > that
> >> > > > > > > > > > were
> >> > > > > > > > > > >> >> added
> >> > > > > > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for
> non
> >> > > > floating
> >> > > > > > > point
> >> > > > > > > > > > types)
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> That is to say it will be available in the
> >> latest
> >> > > open
> >> > > > > > > source
> >> > > > > > > > > > >> writers
> >> > > > > > > > > > >> >> and
> >> > > > > > > > > > >> >> >> readers, but realistically not widely used in
> >> the
> >> > > > > > ecosystem
> >> > > > > > > > > where
> >> > > > > > > > > > >> >> >> compatibility is a concern (a large part)
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> I view Julian's work[2][3] to gather
> consensus
> >> on
> >> > > how
> >> > > > to
> >> > > > > > > name
> >> > > > > > > > > > >> >> >> combinations of features (e.g. "versions") as
> >> the
> >> > > > > > mechanism
> >> > > > > > > by
> >> > > > > > > > > > >> which we
> >> > > > > > > > > > >> >> >> will accelerate the adoption of this change
> >> (along
> >> > > > with
> >> > > > > > > other
> >> > > > > > > > > > >> forward
> >> > > > > > > > > > >> >> >> incompatible changes) across the ecosystem.
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> > Will we exclude this change when cutting
> >> > > > > parquet-format
> >> > > > > > > > > v2.14.0?
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> No I don't think so -- I would expect it to
> go
> >> out
> >> > > in
> >> > > > > the
> >> > > > > > > next
> >> > > > > > > > > > >> >> >> parquet-format version as do other changes in
> >> the
> >> > > > spec.
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> Andrew
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> [1]:
> >> > > > > > https://parquet.apache.org/docs/file-format/versions/
> >> > > > > > > > > > >> >> >> [2]:
> >> > > > > > > > > > >>
> >> > > > > >
> >> https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> >> > > > > > > > > > >> >> >> [3]:
> >> > > > > > > > > > >>
> >> > > > > >
> >> https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora
> >> via
> >> > > dev <
> >> > > > > > > > > > >> >> >> dev@parquet.apache.org> wrote:
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >> >>> Hi Andrew,
> >> > > > > > > > > > >> >> >>>
> >> > > > > > > > > > >> >> >>> How does this interact with the ongoing
> >> > versioning
> >> > > > > > > > discussion?
> >> > > > > > > > > > >> Given
> >> > > > > > > > > > >> >> that
> >> > > > > > > > > > >> >> >>> new encodings are not forward compatible, I
> >> would
> >> > > > > assume
> >> > > > > > > ALP
> >> > > > > > > > is
> >> > > > > > > > > > >> >> included
> >> > > > > > > > > > >> >> >>> in
> >> > > > > > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to
> >> me
> >> > how
> >> > > > > that
> >> > > > > > > > works
> >> > > > > > > > > if
> >> > > > > > > > > > >> it's
> >> > > > > > > > > > >> >> >>> merged to the parquet-format master branch
> >> now.
> >> > > Will
> >> > > > we
> >> > > > > > > > exclude
> >> > > > > > > > > > >> this
> >> > > > > > > > > > >> >> >>> change
> >> > > > > > > > > > >> >> >>> when cutting parquet-format v2.14.0?
> >> > > > > > > > > > >> >> >>>
> >> > > > > > > > > > >> >> >>> -- Div
> >> > > > > > > > > > >> >> >>>
> >> > > > > > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb
> <
> >> > > > > > > > > > >> andrewlamb11@gmail.com>
> >> > > > > > > > > > >> >> >>> wrote:
> >> > > > > > > > > > >> >> >>>
> >> > > > > > > > > > >> >> >>> > Hello,
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>> > As an update, thanks to the epic work from
> >> many
> >> > > > > > > > contributors,
> >> > > > > > > > > > >> >> >>> especially
> >> > > > > > > > > > >> >> >>> > Prateek, I just merged the parquet-format
> >> > change
> >> > > > for
> >> > > > > > > > ALP[1].
> >> > > > > > > > > We
> >> > > > > > > > > > >> >> plan to
> >> > > > > > > > > > >> >> >>> > make additional editorial The remaining
> >> items I
> >> > > > know
> >> > > > > of
> >> > > > > > > are
> >> > > > > > > > > > >> merging
> >> > > > > > > > > > >> >> the
> >> > > > > > > > > > >> >> >>> > examples from parquet-testing[2], and then
> >> of
> >> > > > course
> >> > > > > > the
> >> > > > > > > > > > various
> >> > > > > > > > > > >> >> >>> > implementations
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>> > Thanks again everyone. This is a great
> step
> >> > > forward
> >> > > > > > > > > > >> >> >>> > Andrew
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>> > [1]:
> >> > > > > https://github.com/apache/parquet-format/pull/557
> >> > > > > > > > > > >> >> >>> > [2]:
> >> > > > > > https://github.com/apache/parquet-testing/pull/100
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le
> >> Dem <
> >> > > > > > > > > > julien@apache.org
> >> > > > > > > > > > >> >
> >> > > > > > > > > > >> >> >>> wrote:
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>> > > It was also in my spam folder... :(
> >> > > > > > > > > > >> >> >>> > > I've seen a bunch of apache list emails
> >> go to
> >> > > my
> >> > > > > spam
> >> > > > > > > > > > recently.
> >> > > > > > > > > > >> >> >>> > >
> >> > > > > > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell
> >> > > Spitzer
> >> > > > <
> >> > > > > > > > > > >> >> >>> > > russell.spitzer@gmail.com>
> >> > > > > > > > > > >> >> >>> > > wrote:
> >> > > > > > > > > > >> >> >>> > >
> >> > > > > > > > > > >> >> >>> > > > Yes, my hope was that my vote would
> >> kick it
> >> > > out
> >> > > > > of
> >> > > > > > > spam
> >> > > > > > > > > but
> >> > > > > > > > > > >> we
> >> > > > > > > > > > >> >> >>> > definitely
> >> > > > > > > > > > >> >> >>> > > > had two other votes that also went to
> >> spam
> >> > > for
> >> > > > > me.
> >> > > > > > > > > > >> >> >>> > > >
> >> > > > > > > > > > >> >> >>> > > > For anyone looking the thread is here
> >> > > > > > > > > > >> >> >>> > > >
> >> > > > > > > > > > >> >>
> >> > > > > > >
> >> https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> >> > > > > > > > > > >> >> >>> > > >
> >> > > > > > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah
> >> > > > Kornfield
> >> > > > > <
> >> > > > > > > > > > >> >> >>> > emkornfield@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > wrote:
> >> > > > > > > > > > >> >> >>> > > >
> >> > > > > > > > > > >> >> >>> > > > > I've seen other's votes not go to
> >> spam,
> >> > so
> >> > > > > > > hopefully
> >> > > > > > > > > > people
> >> > > > > > > > > > >> >> will
> >> > > > > > > > > > >> >> >>> see
> >> > > > > > > > > > >> >> >>> > it
> >> > > > > > > > > > >> >> >>> > > > in
> >> > > > > > > > > > >> >> >>> > > > > there inboxes (or see this thread
> and
> >> > look
> >> > > in
> >> > > > > > there
> >> > > > > > > > > > spam).
> >> > > > > > > > > > >> >> >>> > > > >
> >> > > > > > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM
> >> PRATEEK
> >> > > > GAUR <
> >> > > > > > > > > > >> >> >>> prtkgaur@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > wrote:
> >> > > > > > > > > > >> >> >>> > > > >
> >> > > > > > > > > > >> >> >>> > > > > > Okay,
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > I sent out the voting email
> >> yesterday
> >> > and
> >> > > > so
> >> > > > > > far
> >> > > > > > > > I've
> >> > > > > > > > > > >> heard
> >> > > > > > > > > > >> >> >>> from 3
> >> > > > > > > > > > >> >> >>> > > > people
> >> > > > > > > > > > >> >> >>> > > > > > that it ended up in their "spam
> >> > folder".
> >> > > > Dev
> >> > > > > > VPN
> >> > > > > > > to
> >> > > > > > > > > be
> >> > > > > > > > > > >> >> blamed
> >> > > > > > > > > > >> >> >>> for
> >> > > > > > > > > > >> >> >>> > > it?.
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > What's the protocol here?
> >> > > > > > > > > > >> >> >>> > > > > > I let people hunt for the email in
> >> > their
> >> > > > spam
> >> > > > > > > > folder
> >> > > > > > > > > or
> >> > > > > > > > > > >> send
> >> > > > > > > > > > >> >> >>> out
> >> > > > > > > > > > >> >> >>> > > > another
> >> > > > > > > > > > >> >> >>> > > > > > one?
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > Best
> >> > > > > > > > > > >> >> >>> > > > > > Prateek
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM
> >> > PRATEEK
> >> > > > > GAUR <
> >> > > > > > > > > > >> >> >>> prtkgaur@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > wrote:
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > Hi team,
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > Vinoo has added the tests which
> >> were
> >> > > > > > requested
> >> > > > > > > in
> >> > > > > > > > > the
> >> > > > > > > > > > >> last
> >> > > > > > > > > > >> >> >>> round
> >> > > > > > > > > > >> >> >>> > of
> >> > > > > > > > > > >> >> >>> > > > > > review.
> >> > > > > > > > > > >> >> >>> > > > > > > In his own words.
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > "
> >> > > > > > > > > > >> >> >>> > > > > > > The extreme value tests Micah
> >> wanted
> >> > > are
> >> > > > > done
> >> > > > > > > and
> >> > > > > > > > > > >> pushed.
> >> > > > > > > > > > >> >> I
> >> > > > > > > > > > >> >> >>> added
> >> > > > > > > > > > >> >> >>> > > > > > coverage
> >> > > > > > > > > > >> >> >>> > > > > > > for values that need the full
> FOR
> >> bit
> >> > > > width
> >> > > > > > > after
> >> > > > > > > > > the
> >> > > > > > > > > > >> >> frame
> >> > > > > > > > > > >> >> >>> of
> >> > > > > > > > > > >> >> >>> > > > > reference
> >> > > > > > > > > > >> >> >>> > > > > > is
> >> > > > > > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where
> >> the
> >> > > > signed
> >> > > > > > max
> >> > > > > > > > > minus
> >> > > > > > > > > > >> min
> >> > > > > > > > > > >> >> >>> > > subtraction
> >> > > > > > > > > > >> >> >>> > > > > > > overflows), 63-bit (the
> >> non-overflow
> >> > > > case),
> >> > > > > > and
> >> > > > > > > > > > 32-bit
> >> > > > > > > > > > >> for
> >> > > > > > > > > > >> >> >>> > floats.
> >> > > > > > > > > > >> >> >>> > > > All
> >> > > > > > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I
> >> also
> >> > > > > > verified
> >> > > > > > > > them
> >> > > > > > > > > > >> >> through
> >> > > > > > > > > > >> >> >>> Arrow
> >> > > > > > > > > > >> >> >>> > > C++
> >> > > > > > > > > > >> >> >>> > > > > ALP
> >> > > > > > > > > > >> >> >>> > > > > > > reader (the local build), so the
> >> > > > > Java-written
> >> > > > > > > > > extreme
> >> > > > > > > > > > >> >> columns
> >> > > > > > > > > > >> >> >>> > > decode
> >> > > > > > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact
> >> against
> >> > the
> >> > > > > > > expected
> >> > > > > > > > > > >> values."
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > State of the PR (#3397):
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > >    - Merges cleanly with master
> (I
> >> > > pulled
> >> > > > > > > master
> >> > > > > > > > in
> >> > > > > > > > > > and
> >> > > > > > > > > > >> >> >>> resolved
> >> > > > > > > > > > >> >> >>> > > the
> >> > > > > > > > > > >> >> >>> > > > > > >    conflicts).
> >> > > > > > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads
> >> > resolved.
> >> > > > The
> >> > > > > 3
> >> > > > > > > > > > remaining
> >> > > > > > > > > > >> are
> >> > > > > > > > > > >> >> >>> > > > intentional:
> >> > > > > > > > > > >> >> >>> > > > > > >    one deferred perf nit, one
> that
> >> > > stays
> >> > > > > open
> >> > > > > > > > until
> >> > > > > > > > > > >> >> >>> > parquet-format
> >> > > > > > > > > > >> >> >>> > > > > ships
> >> > > > > > > > > > >> >> >>> > > > > > ALP,
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > "
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > With this both the
> >> > > > > > > > > > >> >> >>> > > > > > > 1) C++ PR :
> >> > > > > > > > > > >> >> >>>
> >> > https://github.com/apache/arrow/pull/48345/changes
> >> > > > > > > > > > >> >> >>> > > > > > > 2) Java PR :
> >> > > > > > > > > > >> >> >>>
> >> https://github.com/apache/parquet-java/pull/3397
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > Are cross language tested and
> >> range
> >> > of
> >> > > > test
> >> > > > > > > > > > scenarios.
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > Best
> >> > > > > > > > > > >> >> >>> > > > > > > Prateek
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM
> >> > PRATEEK
> >> > > > > GAUR
> >> > > > > > <
> >> > > > > > > > > > >> >> >>> prtkgaur@gmail.com
> >> > > > > > > > > > >> >> >>> > >
> >> > > > > > > > > > >> >> >>> > > > > wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > >> Thanks Matt,
> >> > > > > > > > > > >> >> >>> > > > > > >>
> >> > > > > > > > > > >> >> >>> > > > > > >> I'll be on it this week.
> >> > > > > > > > > > >> >> >>> > > > > > >>
> >> > > > > > > > > > >> >> >>> > > > > > >> Best
> >> > > > > > > > > > >> >> >>> > > > > > >> Prateek
> >> > > > > > > > > > >> >> >>> > > > > > >>
> >> > > > > > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM
> >> Matt
> >> > > > > Topol <
> >> > > > > > > > > > >> >> >>> > > zotthewizard@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> There is also the Go
> >> implementation
> >> > > > > > submitted
> >> > > > > > > > by
> >> > > > > > > > > > >> Arnav (
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > https://github.com/apache/arrow-go/pull/704)
> >> > > > > > > > > which
> >> > > > > > > > > > >> is
> >> > > > > > > > > > >> >> >>> waiting
> >> > > > > > > > > > >> >> >>> > > for
> >> > > > > > > > > > >> >> >>> > > > > > >>> updates.
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it
> >> didn't
> >> > > get
> >> > > > > lost
> >> > > > > > > > here.
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> --Matt
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at
> 11:30 AM
> >> > > > PRATEEK
> >> > > > > > > GAUR <
> >> > > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > Hi all,
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > I'd like to share a status
> >> update
> >> > > on
> >> > > > > the
> >> > > > > > > ALP
> >> > > > > > > > > > >> encoding
> >> > > > > > > > > > >> >> >>> effort
> >> > > > > > > > > > >> >> >>> > > and
> >> > > > > > > > > > >> >> >>> > > > > get
> >> > > > > > > > > > >> >> >>> > > > > > a
> >> > > > > > > > > > >> >> >>> > > > > > >>> feel
> >> > > > > > > > > > >> >> >>> > > > > > >>> > from the community before
> >> > starting
> >> > > a
> >> > > > > > formal
> >> > > > > > > > > vote.
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > We now have the
> specification
> >> > plus
> >> > > > > > > > > > implementations
> >> > > > > > > > > > >> in
> >> > > > > > > > > > >> >> >>> both
> >> > > > > > > > > > >> >> >>> > > > > languages:
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> >     - Spec:
> >> > > > > > > >  apache/parquet-format#557 —
> >> > > > > > > > > > >> GH-533
> >> > > > > > > > > > >> >> >>> Add
> >> > > > > > > > > > >> >> >>> > ALP
> >> > > > > > > > > > >> >> >>> > > > > > encoding
> >> > > > > > > > > > >> >> >>> > > > > > >>> > specification
> >> > > > > > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):
> >> > > > apache/arrow#48345
> >> > > > > —
> >> > > > > > > > > GH-48701
> >> > > > > > > > > > >> >> >>> > > [C++][Parquet]
> >> > > > > > > > > > >> >> >>> > > > > Add
> >> > > > > > > > > > >> >> >>> > > > > > >>> ALPpd
> >> > > > > > > > > > >> >> >>> > > > > > >>> > encoding
> >> > > > > > > > > > >> >> >>> > > > > > >>> >     - Java:
> >> > > > > > >  apache/parquet-java#3397
> >> > > > > > > > —
> >> > > > > > > > > > >> Parquet
> >> > > > > > > > > > >> >> >>> Java
> >> > > > > > > > > > >> >> >>> > ALP
> >> > > > > > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > Current state:
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation
> >> has
> >> > > been
> >> > > > > > > through
> >> > > > > > > > > 3-4
> >> > > > > > > > > > >> >> rounds
> >> > > > > > > > > > >> >> >>> of
> >> > > > > > > > > > >> >> >>> > > > review.
> >> > > > > > > > > > >> >> >>> > > > > > >>> >     - The Java
> implementation
> >> has
> >> > > > been
> >> > > > > > > > tracking
> >> > > > > > > > > > >> well
> >> > > > > > > > > > >> >> and
> >> > > > > > > > > > >> >> >>> has
> >> > > > > > > > > > >> >> >>> > > had
> >> > > > > > > > > > >> >> >>> > > > > > >>> initial
> >> > > > > > > > > > >> >> >>> > > > > > >>> >       reviews from
> >> contributors,
> >> > > with
> >> > > > > no
> >> > > > > > > > major
> >> > > > > > > > > > >> >> remaining
> >> > > > > > > > > > >> >> >>> > > issues.
> >> > > > > > > > > > >> >> >>> > > > > > >>> >     - Cross-language
> >> > compatibility
> >> > > > > tests
> >> > > > > > > are
> >> > > > > > > > > > >> passing:
> >> > > > > > > > > > >> >> the
> >> > > > > > > > > > >> >> >>> > Arrow
> >> > > > > > > > > > >> >> >>> > > > C++
> >> > > > > > > > > > >> >> >>> > > > > > >>> decoder
> >> > > > > > > > > > >> >> >>> > > > > > >>> >       reads Java-written
> data
> >> > > > > bit-exactly
> >> > > > > > > > > across
> >> > > > > > > > > > >> >> ~1.56M
> >> > > > > > > > > > >> >> >>> > values
> >> > > > > > > > > > >> >> >>> > > > and
> >> > > > > > > > > > >> >> >>> > > > > 18
> >> > > > > > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1
> >> and
> >> > V2
> >> > > > > pages,
> >> > > > > > > > > > multiple
> >> > > > > > > > > > >> >> vector
> >> > > > > > > > > > >> >> >>> > > sizes,
> >> > > > > > > > > > >> >> >>> > > > > and
> >> > > > > > > > > > >> >> >>> > > > > > >>> > several
> >> > > > > > > > > > >> >> >>> > > > > > >>> >       real datasets — zero
> >> > > > mismatches.
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we
> >> will
> >> > > be
> >> > > > > > adding
> >> > > > > > > > > > >> coverage
> >> > > > > > > > > > >> >> for
> >> > > > > > > > > > >> >> >>> > > extreme
> >> > > > > > > > > > >> >> >>> > > > > > values
> >> > > > > > > > > > >> >> >>> > > > > > >>> > (those requiring
> >> > > > > > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is
> >> applied)
> >> > > > > before
> >> > > > > > we
> >> > > > > > > > > > close a
> >> > > > > > > > > > >> >> vote.
> >> > > > > > > > > > >> >> >>> > We'll
> >> > > > > > > > > > >> >> >>> > > > aim
> >> > > > > > > > > > >> >> >>> > > > > > to
> >> > > > > > > > > > >> >> >>> > > > > > >>> get
> >> > > > > > > > > > >> >> >>> > > > > > >>> > that
> >> > > > > > > > > > >> >> >>> > > > > > >>> >  done in parallel.
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > Plan: unless there are
> >> > objections,
> >> > > I
> >> > > > > > intend
> >> > > > > > > > to
> >> > > > > > > > > > >> start a
> >> > > > > > > > > > >> >> >>> vote
> >> > > > > > > > > > >> >> >>> > at
> >> > > > > > > > > > >> >> >>> > > > the
> >> > > > > > > > > > >> >> >>> > > > > > end
> >> > > > > > > > > > >> >> >>> > > > > > >>> of
> >> > > > > > > > > > >> >> >>> > > > > > >>> > this week/early
> >> > > > > > > > > > >> >> >>> > > > > > >>> > next week.
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > Thanks
> >> > > > > > > > > > >> >> >>> > > > > > >>> > Prateek
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at
> 8:50 AM
> >> > > > PRATEEK
> >> > > > > > > GAUR <
> >> > > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > Hi Team,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide
> some
> >> > > updates
> >> > > > > on
> >> > > > > > > ALP.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4
> >> > rounds
> >> > > of
> >> > > > > > > review
> >> > > > > > > > > for
> >> > > > > > > > > > >> the
> >> > > > > > > > > > >> >> c++
> >> > > > > > > > > > >> >> >>> PR :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > https://github.com/apache/arrow/pull/48345
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > For the Java
> implementation
> >> > Vinoo
> >> > > > has
> >> > > > > > > been
> >> > > > > > > > > > >> working
> >> > > > > > > > > > >> >> on
> >> > > > > > > > > > >> >> >>> > > following
> >> > > > > > > > > > >> >> >>> > > > > PR
> >> > > > > > > > > > >> >> >>> > > > > > :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > https://github.com/apache/parquet-java/pull/3397
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > Best
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > Prateek
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at
> >> 1:50 PM
> >> > > > Micah
> >> > > > > > > > > Kornfield
> >> > > > > > > > > > <
> >> > > > > > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > > wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the
> question
> >> > was
> >> > > > > > already
> >> > > > > > > > > asked,
> >> > > > > > > > > > >> but
> >> > > > > > > > > > >> >> >>> should
> >> > > > > > > > > > >> >> >>> > we
> >> > > > > > > > > > >> >> >>> > > > > care
> >> > > > > > > > > > >> >> >>> > > > > > >>> about
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can
> >> FLOAT +
> >> > > ALP
> >> > > > > be
> >> > > > > > > more
> >> > > > > > > > > > >> >> efficient
> >> > > > > > > > > > >> >> >>> than
> >> > > > > > > > > > >> >> >>> > > > > FLOAT16
> >> > > > > > > > > > >> >> >>> > > > > > +
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4
> >> for
> >> > > > > example?
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we
> >> could
> >> > > defer
> >> > > > > it
> >> > > > > > > for
> >> > > > > > > > > the
> >> > > > > > > > > > >> >> >>> following
> >> > > > > > > > > > >> >> >>> > > > reasons:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there
> >> are a
> >> > > lot
> >> > > > > of
> >> > > > > > > easy
> >> > > > > > > > > > >> >> reference
> >> > > > > > > > > > >> >> >>> > > datasets
> >> > > > > > > > > > >> >> >>> > > > to
> >> > > > > > > > > > >> >> >>> > > > > > >>> test
> >> > > > > > > > > > >> >> >>> > > > > > >>> > its
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does
> >> look
> >> > > like
> >> > > > > > there
> >> > > > > > > > > might
> >> > > > > > > > > > be
> >> > > > > > > > > > >> >> one
> >> > > > > > > > > > >> >> >>> or
> >> > > > > > > > > > >> >> >>> > two
> >> > > > > > > > > > >> >> >>> > > on
> >> > > > > > > > > > >> >> >>> > > > > > >>> > huggingface
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> (e.g.
> >> > > > > > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> >> > > > > > > > > > >> >> >>> ).
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that
> >> > float
> >> > > 16
> >> > > > > was
> >> > > > > > > > more
> >> > > > > > > > > > >> likely
> >> > > > > > > > > > >> >> >>> used
> >> > > > > > > > > > >> >> >>> > for
> >> > > > > > > > > > >> >> >>> > > > > values
> >> > > > > > > > > > >> >> >>> > > > > > >>> that
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> were less likely to
> reduce
> >> to
> >> > > > > decimal
> >> > > > > > > > > values.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as
> an
> >> > > > > extension
> >> > > > > > > > later
> >> > > > > > > > > if
> >> > > > > > > > > > >> >> needed.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> Cheers,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> Micah
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at
> >> 1:40 PM
> >> > > > > Antoine
> >> > > > > > > > > Pitrou
> >> > > > > > > > > > <
> >> > > > > > > > > > >> >> >>> > > > > antoine@python.org
> >> > > > > > > > > > >> >> >>> > > > > > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Hello,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the
> question
> >> > was
> >> > > > > > already
> >> > > > > > > > > asked,
> >> > > > > > > > > > >> but
> >> > > > > > > > > > >> >> >>> should
> >> > > > > > > > > > >> >> >>> > we
> >> > > > > > > > > > >> >> >>> > > > > care
> >> > > > > > > > > > >> >> >>> > > > > > >>> about
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can
> >> FLOAT +
> >> > > ALP
> >> > > > > be
> >> > > > > > > more
> >> > > > > > > > > > >> >> efficient
> >> > > > > > > > > > >> >> >>> than
> >> > > > > > > > > > >> >> >>> > > > > FLOAT16
> >> > > > > > > > > > >> >> >>> > > > > > +
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4
> >> for
> >> > > > > example?
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Regards
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10,
> >> > PRATEEK
> >> > > > > GAUR
> >> > > > > > a
> >> > > > > > > > > écrit
> >> > > > > > > > > > :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and
> Micah
> >> > for
> >> > > > > review
> >> > > > > > > > > > feedback
> >> > > > > > > > > > >> on
> >> > > > > > > > > > >> >> >>> the two
> >> > > > > > > > > > >> >> >>> > > > PR's
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> https://github.com/apache/arrow/pull/48345/changes
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format
> >> repo)
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >>
> https://github.com/apache/parquet-format/pull/557
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all
> >> > > (unless I
> >> > > > > > > missed
> >> > > > > > > > > > >> >> something)
> >> > > > > > > > > > >> >> >>> > > comments
> >> > > > > > > > > > >> >> >>> > > > on
> >> > > > > > > > > > >> >> >>> > > > > > >>> the two
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > PR's.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Best
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026
> at
> >> > > > 1:08 PM
> >> > > > > > > > PRATEEK
> >> > > > > > > > > > >> GAUR <
> >> > > > > > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and
> >> Micah.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of
> >> feedback
> >> > on
> >> > > > at
> >> > > > > > > least
> >> > > > > > > > > the
> >> > > > > > > > > > >> >> >>> > > implementations`
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have
> >> > already
> >> > > > > > started
> >> > > > > > > > > > >> addressing
> >> > > > > > > > > > >> >> the
> >> > > > > > > > > > >> >> >>> > > > > feedback, I
> >> > > > > > > > > > >> >> >>> > > > > > >>> > should
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> be
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> done with that
> >> > > > Monday/Tuesday.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too
> has
> >> > been
> >> > > > > making
> >> > > > > > > > good
> >> > > > > > > > > > >> >> progress
> >> > > > > > > > > > >> >> >>> on
> >> > > > > > > > > > >> >> >>> > the
> >> > > > > > > > > > >> >> >>> > > > Java
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > implementation.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Best
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026
> >> at
> >> > > > > 12:55 PM
> >> > > > > > > > Andrew
> >> > > > > > > > > > >> Lamb <
> >> > > > > > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you
> for
> >> > the
> >> > > > > > > > > clarification
> >> > > > > > > > > > >> -- I
> >> > > > > > > > > > >> >> >>> will
> >> > > > > > > > > > >> >> >>> > try
> >> > > > > > > > > > >> >> >>> > > > and
> >> > > > > > > > > > >> >> >>> > > > > > look
> >> > > > > > > > > > >> >> >>> > > > > > >>> > into
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> the
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> >> > > > > > > implementation[1]
> >> > > > > > > > in
> >> > > > > > > > > > >> this
> >> > > > > > > > > > >> >> next
> >> > > > > > > > > > >> >> >>> > week
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> >> > > > > > > > > > >> >> >>>
> https://github.com/apache/arrow-rs/pull/9372
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25,
> 2026
> >> at
> >> > > > > 12:01 PM
> >> > > > > > > > Micah
> >> > > > > > > > > > >> >> >>> Kornfield <
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a
> >> fair
> >> > > > > amount
> >> > > > > > of
> >> > > > > > > > > > >> feedback
> >> > > > > > > > > > >> >> on
> >> > > > > > > > > > >> >> >>> at
> >> > > > > > > > > > >> >> >>> > > least
> >> > > > > > > > > > >> >> >>> > > > > the
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations,
> >> > > typically
> >> > > > I
> >> > > > > > > think
> >> > > > > > > > > > we've
> >> > > > > > > > > > >> >> waited
> >> > > > > > > > > > >> >> >>> > till
> >> > > > > > > > > > >> >> >>> > > > they
> >> > > > > > > > > > >> >> >>> > > > > > are
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> close to
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a
> >> > final
> >> > > > > vote.
> >> > > > > > > > > > >> Otherwise I
> >> > > > > > > > > > >> >> >>> agree
> >> > > > > > > > > > >> >> >>> > we
> >> > > > > > > > > > >> >> >>> > > > are
> >> > > > > > > > > > >> >> >>> > > > > > very
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> close.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April
> >> 25,
> >> > > > 2026,
> >> > > > > > > Andrew
> >> > > > > > > > > > Lamb
> >> > > > > > > > > > >> <
> >> > > > > > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this
> >> > > content
> >> > > > it
> >> > > > > > > looks
> >> > > > > > > > > to
> >> > > > > > > > > > me
> >> > > > > > > > > > >> >> like
> >> > > > > > > > > > >> >> >>> we
> >> > > > > > > > > > >> >> >>> > are
> >> > > > > > > > > > >> >> >>> > > > > ready
> >> > > > > > > > > > >> >> >>> > > > > > >>> to
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> start a
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to
> explicitly
> >> > > accept
> >> > > > > ALP
> >> > > > > > > into
> >> > > > > > > > > > >> Parquet
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know
> >> of a
> >> > > > reason
> >> > > > > > we
> >> > > > > > > > > should
> >> > > > > > > > > > >> >> >>> postpone it
> >> > > > > > > > > > >> >> >>> > > for
> >> > > > > > > > > > >> >> >>> > > > > > >>> longer?
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone
> >> needs
> >> > > some
> >> > > > > > more
> >> > > > > > > > time
> >> > > > > > > > > > to
> >> > > > > > > > > > >> >> >>> review?
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22,
> >> 2026
> >> > at
> >> > > > > > 1:00 PM
> >> > > > > > > > > > PRATEEK
> >> > > > > > > > > > >> >> GAUR <
> >> > > > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is
> >> > doing
> >> > > > > well.
> >> > > > > > I
> >> > > > > > > > got
> >> > > > > > > > > a
> >> > > > > > > > > > >> >> chance
> >> > > > > > > > > > >> >> >>> to
> >> > > > > > > > > > >> >> >>> > work
> >> > > > > > > > > > >> >> >>> > > > > > >>> through all
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> the
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining
> feedback
> >> > and
> >> > > > > update
> >> > > > > > > the
> >> > > > > > > > > > spec
> >> > > > > > > > > > >> >> doc.
> >> > > > > > > > > > >> >> >>> Here
> >> > > > > > > > > > >> >> >>> > > are
> >> > > > > > > > > > >> >> >>> > > > > the
> >> > > > > > > > > > >> >> >>> > > > > > >>> new
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > artifacts
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec
> document :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > >
> >> > > > > > > > > > >> >> >>> > > >
> >> > > > > > > > > > >> >> >>> > >
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>>
> >> > > > > > > > > > >> >>
> >> > > > > > > > > > >>
> >> > > > > > > > > >
> >> > > > > > > > >
> >> > > > > > > >
> >> > > > > > >
> >> > > > > >
> >> > > > > https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-
> >> > > > 3fPtD_aWt/edit
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document
> >> in
> >> > > > parquet
> >> > > > > > > > format
> >> > > > > > > > > > >> repo :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> >
> >> > > https://github.com/apache/parquet-format/pull/557
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp
> >> implementation
> >> > > in
> >> > > > > > arrow
> >> > > > > > > > c++
> >> > > > > > > > > > >> repo :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> >
> >> > > https://github.com/apache/arrow/pull/48345/changes
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp
> >> implementation
> >> > > in
> >> > > > > > > > > parquet-java
> >> > > > > > > > > > >> >> repo :
> >> > > > > > > > > > >> >> >>> Work
> >> > > > > > > > > > >> >> >>> > > for
> >> > > > > > > > > > >> >> >>> > > > > > >>> Vinoo and
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Julien
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> >
> >> > https://github.com/apache/parquet-java/pull/3397
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test
> >> and
> >> > > > > > > benchmarking
> >> > > > > > > > > > >> >> artifacts in
> >> > > > > > > > > > >> >> >>> > > > > > >>> parquet-testing
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> repo :
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> >
> >> > > https://github.com/apache/parquet-testing/pull/100
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav
> >> just
> >> > > > > > submitted
> >> > > > > > > > an
> >> > > > > > > > > in
> >> > > > > > > > > > >> >> >>> progress
> >> > > > > > > > > > >> >> >>> > > > > > >>> implementation
> >> > > > > > > > > > >> >> >>> > > > > > >>> > in
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> Go.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> https://github.com/apache/arrow-go/pull/704
> >> > > > > > > > > > >> >> >>> > (I
> >> > > > > > > > > > >> >> >>> > > > > > haven't
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> started
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     looking at
> it
> >> > yet)
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Rust : I
> >> > remember
> >> > > > > > Andrew
> >> > > > > > > > > > >> mentioned
> >> > > > > > > > > > >> >> that
> >> > > > > > > > > > >> >> >>> > this
> >> > > > > > > > > > >> >> >>> > > > work
> >> > > > > > > > > > >> >> >>> > > > > > is
> >> > > > > > > > > > >> >> >>> > > > > > >>> also
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> in
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     progress
> (So 4
> >> > > > > > languages!)
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Arrow C++
> >> > > > implementation *
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> The PR is out
> and
> >> was
> >> > > > also
> >> > > > > > used
> >> > > > > > > > by
> >> > > > > > > > > > >> >> Antoine to
> >> > > > > > > > > > >> >> >>> > > report
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> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8
> Feb
> >> > 2026
> >> > > at
> >> > > > > > > 18:12,
> >> > > > > > > > > > Micah
> >> > > > > > > > > > >> >> >>> Kornfield
> >> > > > > > > > > > >> >> >>> > <
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> >> > > emkornfield@gmail.com>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks
> like
> >> > the
> >> > > > > actual
> >> > > > > > > > issue
> >> > > > > > > > > > >> >> >>> described for
> >> > > > > > > > > > >> >> >>> > > ORC
> >> > > > > > > > > > >> >> >>> > > > > in
> >> > > > > > > > > > >> >> >>> > > > > > >>> the
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> paper
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has
> multiple
> >> > > > > > sub-encodings
> >> > > > > > > > in
> >> > > > > > > > > a
> >> > > > > > > > > > >> >> batch.
> >> > > > > > > > > > >> >> >>> This
> >> > > > > > > > > > >> >> >>> > > is
> >> > > > > > > > > > >> >> >>> > > > > > >>> different
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> then
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed
> here
> >> > > where
> >> > > > > > there
> >> > > > > > > is
> >> > > > > > > > > > still
> >> > > > > > > > > > >> >> fixed
> >> > > > > > > > > > >> >> >>> > > > encoding
> >> > > > > > > > > > >> >> >>> > > > > > per
> >> > > > > > > > > > >> >> >>> > > > > > >>> page
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> in
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given
> >> reasonably
> >> > > > sized
> >> > > > > > > > pages I
> >> > > > > > > > > > >> don't
> >> > > > > > > > > > >> >> >>> think
> >> > > > > > > > > > >> >> >>> > > > branch
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction
> >> > should
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue
> for
> >> > new
> >> > > > > > > encodings.
> >> > > > > > > > > I
> >> > > > > > > > > > >> agree
> >> > > > > > > > > > >> >> >>> that
> >> > > > > > > > > > >> >> >>> > we
> >> > > > > > > > > > >> >> >>> > > > > should
> >> > > > > > > > > > >> >> >>> > > > > > >>> be
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative
> in
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for
> >> > adding
> >> > > > new
> >> > > > > > > > > > encodings.
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> >> > > > > > > > > > >> >> >>> > > > > > >>> > >
> >> > > > > > > > > > >> >> >>> > > > > > >>> >
> >> > > > > > > > > > >> >> >>> > > > > > >>>
> >> > > > > > > > > > >> >> >>> > > > > > >>
> >> > > > > > > > > > >> >> >>> > > > > >
> >> > > > > > > > > > >> >> >>> > > > >
> >> > > > > > > > > > >> >> >>> > > >
> >> > > > > > > > > > >> >> >>> > >
> >> > > > > > > > > > >> >> >>> >
> >> > > > > > > > > > >> >> >>>
> >> > > > > > > > > > >> >> >>
> >> > > > > > > > > > >> >>
> >> > > > > > > > > > >> >
> >> > > > > > > > > > >>
> >> > > > > > > > > > >
> >> > > > > > > > > >
> >> > > > > > > > >
> >> > > > > > > >
> >> > > > > > >
> >> > > > > >
> >> > > > >
> >> > > >
> >> > >
> >> >
> >>
> >
>

Re: [Parquet] ALP Encoding for Floating point data

[Gunnar Morling via dev <de...@parquet.apache.org>]

Hey Gang,

Yeah, agreed, I think it's more similar in the sense that we take the
samples for the preset from across the whole chunk instead of only from its
first segment. AFAIK, DuckDB also resamples and then uses dedicated presets
for specific segments, which can yield even better results but also is more
costly.

As for a perf comparison, I have a quick informal (LLM-coded)
microbenchmark of parquet-java's and Hardwood's ALP decoders and encoders
in this draft PR [1]. In that benchmark, in a Docker container on my
laptop, Hardwood decodes 5–6× faster than parquet-java and encodes a page
2–4× faster once both presets exist (pages purely in memory, no
compression, etc.). Based on some quick profiling, IIUC, it mostly comes
down to bit unpacking on decode (generic 8-at-a-time BytePacker plus a
separate decode pass vs. one fused loop with a single 8-byte load per
value), and on encode to parquet-java evaluating each preset pair on the
full vector rather than a sample.

Numbers may look different elsewhere, so I'd be curious to learn about your
results, also if there's something to do better in the benchmark itself,
etc.

Best,

--Gunnar

[1] https://github.com/hardwood-hq/hardwood/pull/1775


On Thu, 12 Nov 2026 at 13:42, Gang Wu <us...@gmail.com> wrote:

> Thanks Gunnar for sharing this!
>
> I think the encoder approach used by Hardwood looks more similar to the ALP
> paper where all 102,400 values are buffered to decide best presets and then
> encode every vector based on those presets.
>
> I'm trying to improve the ALP implementations on the Parquet C++ side:
> https://github.com/apache/arrow/pull/55449. So I'm really interested
> if you have any document on performance comparison among different
> implementations.
>
> Thanks!
> Gang
>
> On Thu, Nov 12, 2026 at 6:50 PM Gunnar Morling via dev <
> dev@parquet.apache.org> wrote:
>
>> Hey all,
>>
>> We've added ALP encoding and decoding support to Hardwood too [1], [2].
>> Interop with parquet-java's implementation looks good: Hardwood decodes
>> pages written by parquet-java's ALP writer bit-exactly and vice versa.
>>
>> Perhaps interesting: on the encoder side, we build the preset of a column
>> chunk from eight sample vectors distributed across the entire chunk (easy
>> in our case, as Hardwood's writer buffers whole chunks), whereas, IIUC,
>> parquet-java only samples within the first ~110K values of a chunk.
>> Depending on the data distribution, this can yield a more efficient
>> encoding, for instance when a high-cardinality column changes character
>> midway, e.g. moving from two to four decimal places (about 2.8× smaller in
>> a synthetic test with 1M doubles).
>>
>> Best,
>>
>> --Gunnar
>>
>> [1] https://github.com/hardwood-hq/hardwood/pull/1496
>> [2] https://github.com/hardwood-hq/hardwood/pull/1769
>>
>>
>> On Thu, 12 Nov 2026 at 07:01, PRATEEK GAUR <pr...@gmail.com> wrote:
>>
>> > Thanks everyone!
>> >
>> > On Mon, Nov 9, 2026 at 11:58 AM Vinoo Ganesh <vi...@gmail.com>
>> > wrote:
>> >
>> > > Thanks everyone!
>> > >
>> > > Thanks,
>> > > Vinoo Ganesh | vinoo.ganesh@gmail.com
>> > >
>> > > <Vi...@gmail.com>
>> > >
>> > >
>> > > On Mon, Nov 9, 2026 at 2:49 PM Andrew Lamb <an...@gmail.com>
>> > wrote:
>> > >
>> > > > The Java implementation was just merged[1]!
>> > > >
>> > > > Thank you Gang, Vinoo, Prateek and everyone who helped push that one
>> > > along
>> > > >
>> > > > Andrew
>> > > >
>> > > > [1]:
>> > https://github.com/apache/parquet-java/pull/3397#event-35545451335
>> > > >
>> > > > On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <pr...@gmail.com>
>> > > wrote:
>> > > >
>> > > > > Hi team,
>> > > > >
>> > > > > Quick update re: the C++ implementation.
>> > > > > Thanks to all the reviewers, we merged the C++ implementation
>> today.
>> > > > > There are a few follow-up items that I'll address in a subsequent
>> PR.
>> > > > >
>> > > > > Thanks
>> > > > > Prateek
>> > > > >
>> > > > > On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <
>> vinoo.ganesh@gmail.com
>> > >
>> > > > > wrote:
>> > > > >
>> > > > > > Quick update re: the Java impl. Thanks for the feedback, on
>> > > > > > https://github.com/apache/parquet-java/pull/3397, Russel! I
>> pulled
>> > > > > > https://github.com/apache/parquet-java/pull/3791 into its own
>> PR
>> > > > (thanks
>> > > > > > for the quick approval too, Gang). Assuming no objections, I
>> think
>> > we
>> > > > can
>> > > > > > merge #3791, and then go ahead of #3397.
>> > > > > >
>> > > > > > Thanks,
>> > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
>> > > > > >
>> > > > > > <Vi...@gmail.com>
>> > > > > >
>> > > > > >
>> > > > > > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <
>> prtkgaur@gmail.com>
>> > > > wrote:
>> > > > > >
>> > > > > > > [Rust] Awesome thanks Andrew, Kostas and Devin.
>> > > > > > > [Java] Thanks Gang for the feedback on Java PR.
>> > > > > > > [C++] Thanks Gang for another round of feedback on the C++
>> one.
>> > > > > > > [Go] Arnav and I will be working on the golang impl this week.
>> > > > > > >
>> > > > > > > This is great progress all around.
>> > > > > > >
>> > > > > > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <
>> > > vinoo.ganesh@gmail.com>
>> > > > > > > wrote:
>> > > > > > >
>> > > > > > > > Thanks all - I'm addressing Gang's comments on
>> > > > > > > > https://github.com/apache/parquet-java/pull/3397 now, so
>> > > hopefully
>> > > > > > well
>> > > > > > > > also be in a good state for merging the java implementation
>> > soon.
>> > > > > > > >
>> > > > > > > > Thanks,
>> > > > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
>> > > > > > > >
>> > > > > > > > <Vi...@gmail.com>
>> > > > > > > >
>> > > > > > > >
>> > > > > > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <
>> > > andrewlamb11@gmail.com
>> > > > >
>> > > > > > > wrote:
>> > > > > > > >
>> > > > > > > > > We just merged the Rust implementation[1] from Kosta and
>> > Devan.
>> > > > > With
>> > > > > > > the
>> > > > > > > > > imminent release of Parquet Format 2.14.0 I think we'll be
>> > well
>> > > > on
>> > > > > > our
>> > > > > > > > way.
>> > > > > > > > >
>> > > > > > > > > Thanks again for pushing this along,
>> > > > > > > > > Andrew
>> > > > > > > > >
>> > > > > > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
>> > > > > > > > >
>> > > > > > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <
>> > > prtkgaur@gmail.com>
>> > > > > > > wrote:
>> > > > > > > > >
>> > > > > > > > > > Hi team,
>> > > > > > > > > >
>> > > > > > > > > > Thanks Micah for multiple rounds of review and thanks
>> Gang
>> > > for
>> > > > > > > taking a
>> > > > > > > > > > look at the PR and giving feedback. I've addressed all
>> > > comments
>> > > > > in
>> > > > > > > the
>> > > > > > > > > PR.
>> > > > > > > > > > Looking forward to the next round of feedback (or
>> > approval).
>> > > > > Would
>> > > > > > > like
>> > > > > > > > > to
>> > > > > > > > > > get it in soon.
>> > > > > > > > > >
>> > > > > > > > > > https://github.com/apache/arrow/pull/48345/changes
>> > > > > > > > > >
>> > > > > > > > > > With this done and after talking to Arnav, I plan to
>> spend
>> > > some
>> > > > > > time
>> > > > > > > on
>> > > > > > > > > the
>> > > > > > > > > > ALP implementation in the arrow-go repository helping
>> > spread
>> > > > the
>> > > > > > > > support
>> > > > > > > > > to
>> > > > > > > > > > more languages.
>> > > > > > > > > >
>> > > > > > > > > > Best
>> > > > > > > > > > Prateek
>> > > > > > > > > >
>> > > > > > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <
>> > > > prtkgaur@gmail.com
>> > > > > >
>> > > > > > > > wrote:
>> > > > > > > > > >
>> > > > > > > > > > > Thanks Divjot for bringing it up.
>> > > > > > > > > > >
>> > > > > > > > > > > I was under the same impression as Russell and Andrew
>> > that
>> > > > we'd
>> > > > > > > have
>> > > > > > > > it
>> > > > > > > > > > > flag gated.
>> > > > > > > > > > > With the new versioning proposal 'preview' might be a
>> > good
>> > > > tag
>> > > > > > for
>> > > > > > > > it.
>> > > > > > > > > > >
>> > > > > > > > > > > Best
>> > > > > > > > > > > Prateek
>> > > > > > > > > > >
>> > > > > > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
>> > > > > > > andrewlamb11@gmail.com>
>> > > > > > > > > > > wrote:
>> > > > > > > > > > >
>> > > > > > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1]
>> > > (using a
>> > > > > > > comment
>> > > > > > > > > in
>> > > > > > > > > > >> the
>> > > > > > > > > > >> spec section).
>> > > > > > > > > > >>
>> > > > > > > > > > >> Russel: That is my understanding as well.
>> > > > > > > > > > >>
>> > > > > > > > > > >> Hopefully we are able to formalize the versioning
>> > process
>> > > > > > shortly
>> > > > > > > so
>> > > > > > > > > we
>> > > > > > > > > > >> can
>> > > > > > > > > > >> formalize the notion of "preview"
>> > > > > > > > > > >>
>> > > > > > > > > > >> Andrew
>> > > > > > > > > > >>
>> > > > > > > > > > >>
>> > > > > > > > > > >> [1]:
>> https://github.com/apache/parquet-format/pull/604
>> > > > > > > > > > >>
>> > > > > > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
>> > > > > > > > > > >> russell.spitzer@gmail.com>
>> > > > > > > > > > >> wrote:
>> > > > > > > > > > >>
>> > > > > > > > > > >> > I thought we had agreed it would be merged, and
>> > features
>> > > > > like
>> > > > > > > this
>> > > > > > > > > > would
>> > > > > > > > > > >> > be feature flag gated. So a V-Old writer could
>> always
>> > > opt
>> > > > in
>> > > > > > to
>> > > > > > > > > using
>> > > > > > > > > > >> this
>> > > > > > > > > > >> > encoding but that must be a conscious effort if you
>> > are
>> > > > not
>> > > > > > > using
>> > > > > > > > > > VNext
>> > > > > > > > > > >> of
>> > > > > > > > > > >> > Parquet. If you are on V-Next the writer can
>> choose to
>> > > use
>> > > > > ALP
>> > > > > > > > > > whenever
>> > > > > > > > > > >> it
>> > > > > > > > > > >> > likes without user intervention.
>> > > > > > > > > > >> >
>> > > > > > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via
>> dev <
>> > > > > > > > > > >> > dev@parquet.apache.org> wrote:
>> > > > > > > > > > >> >
>> > > > > > > > > > >> >> Yes, that’s my understanding as well. However, as
>> you
>> > > > > noted,
>> > > > > > > the
>> > > > > > > > > > >> >> versioning
>> > > > > > > > > > >> >> discussion is still in early stages and hasn’t
>> > > prescribed
>> > > > > > > > concrete
>> > > > > > > > > > >> >> mechanisms yet. If ALP goes into parquet-format
>> > 2.14.0,
>> > > > > > there’s
>> > > > > > > > no
>> > > > > > > > > > >> >> indication that it’s in preview or that writers
>> > > shouldn’t
>> > > > > use
>> > > > > > > it
>> > > > > > > > by
>> > > > > > > > > > >> >> default
>> > > > > > > > > > >> >> yet. Given that we’ve held off on merging other
>> > > > > incompatible
>> > > > > > > > > changes
>> > > > > > > > > > >> (e.g
>> > > > > > > > > > >> >> removal of path_in_schema) until the versioning
>> > > > discussion
>> > > > > > > > closes,
>> > > > > > > > > my
>> > > > > > > > > > >> >> preference would be to leave ALP un-merged for the
>> > time
>> > > > > being
>> > > > > > > as
>> > > > > > > > > > well.
>> > > > > > > > > > >> >>
>> > > > > > > > > > >> >> — Div
>> > > > > > > > > > >> >>
>> > > > > > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
>> > > > > > > > andrewlamb11@gmail.com>
>> > > > > > > > > > >> wrote:
>> > > > > > > > > > >> >>
>> > > > > > > > > > >> >> > After re-reading Julien's Versioning Proposal,
>> my
>> > > > > > > understanding
>> > > > > > > > > is
>> > > > > > > > > > >> that
>> > > > > > > > > > >> >> if
>> > > > > > > > > > >> >> > we adopt that system, we will somehow mark ALP
>> in
>> > > > > "Preview"
>> > > > > > > in
>> > > > > > > > > > >> >> > parquet-format for release Version 3.
>> > > > > > > > > > >> >> >
>> > > > > > > > > > >> >> > The versioning document doesn't seem to
>> proscribe
>> > the
>> > > > > > > > particular
>> > > > > > > > > > >> method
>> > > > > > > > > > >> >> > for annotating "preview" features -- I think
>> > clearly
>> > > > > > marking
>> > > > > > > > them
>> > > > > > > > > > as
>> > > > > > > > > > >> >> such
>> > > > > > > > > > >> >> > in parquet.thrift as well as reflecting that on
>> the
>> > > > > > > > > > >> >> >
>> > > https://parquet.apache.org/docs/file-format/versions/
>> > > > > page
>> > > > > > > > > somehow
>> > > > > > > > > > >> >> would
>> > > > > > > > > > >> >> > be adequate.
>> > > > > > > > > > >> >> >
>> > > > > > > > > > >> >> > Andrew
>> > > > > > > > > > >> >> >
>> > > > > > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
>> > > > > > > > > > andrewlamb11@gmail.com
>> > > > > > > > > > >> >
>> > > > > > > > > > >> >> > wrote:
>> > > > > > > > > > >> >> >
>> > > > > > > > > > >> >> >> In my mind ALP is in the same position as other
>> > > > > encodings
>> > > > > > > that
>> > > > > > > > > > were
>> > > > > > > > > > >> >> added
>> > > > > > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non
>> > > > floating
>> > > > > > > point
>> > > > > > > > > > types)
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> That is to say it will be available in the
>> latest
>> > > open
>> > > > > > > source
>> > > > > > > > > > >> writers
>> > > > > > > > > > >> >> and
>> > > > > > > > > > >> >> >> readers, but realistically not widely used in
>> the
>> > > > > > ecosystem
>> > > > > > > > > where
>> > > > > > > > > > >> >> >> compatibility is a concern (a large part)
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> I view Julian's work[2][3] to gather consensus
>> on
>> > > how
>> > > > to
>> > > > > > > name
>> > > > > > > > > > >> >> >> combinations of features (e.g. "versions") as
>> the
>> > > > > > mechanism
>> > > > > > > by
>> > > > > > > > > > >> which we
>> > > > > > > > > > >> >> >> will accelerate the adoption of this change
>> (along
>> > > > with
>> > > > > > > other
>> > > > > > > > > > >> forward
>> > > > > > > > > > >> >> >> incompatible changes) across the ecosystem.
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> > Will we exclude this change when cutting
>> > > > > parquet-format
>> > > > > > > > > v2.14.0?
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> No I don't think so -- I would expect it to go
>> out
>> > > in
>> > > > > the
>> > > > > > > next
>> > > > > > > > > > >> >> >> parquet-format version as do other changes in
>> the
>> > > > spec.
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> Andrew
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> [1]:
>> > > > > > https://parquet.apache.org/docs/file-format/versions/
>> > > > > > > > > > >> >> >> [2]:
>> > > > > > > > > > >>
>> > > > > >
>> https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
>> > > > > > > > > > >> >> >> [3]:
>> > > > > > > > > > >>
>> > > > > >
>> https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora
>> via
>> > > dev <
>> > > > > > > > > > >> >> >> dev@parquet.apache.org> wrote:
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >> >>> Hi Andrew,
>> > > > > > > > > > >> >> >>>
>> > > > > > > > > > >> >> >>> How does this interact with the ongoing
>> > versioning
>> > > > > > > > discussion?
>> > > > > > > > > > >> Given
>> > > > > > > > > > >> >> that
>> > > > > > > > > > >> >> >>> new encodings are not forward compatible, I
>> would
>> > > > > assume
>> > > > > > > ALP
>> > > > > > > > is
>> > > > > > > > > > >> >> included
>> > > > > > > > > > >> >> >>> in
>> > > > > > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to
>> me
>> > how
>> > > > > that
>> > > > > > > > works
>> > > > > > > > > if
>> > > > > > > > > > >> it's
>> > > > > > > > > > >> >> >>> merged to the parquet-format master branch
>> now.
>> > > Will
>> > > > we
>> > > > > > > > exclude
>> > > > > > > > > > >> this
>> > > > > > > > > > >> >> >>> change
>> > > > > > > > > > >> >> >>> when cutting parquet-format v2.14.0?
>> > > > > > > > > > >> >> >>>
>> > > > > > > > > > >> >> >>> -- Div
>> > > > > > > > > > >> >> >>>
>> > > > > > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
>> > > > > > > > > > >> andrewlamb11@gmail.com>
>> > > > > > > > > > >> >> >>> wrote:
>> > > > > > > > > > >> >> >>>
>> > > > > > > > > > >> >> >>> > Hello,
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>> > As an update, thanks to the epic work from
>> many
>> > > > > > > > contributors,
>> > > > > > > > > > >> >> >>> especially
>> > > > > > > > > > >> >> >>> > Prateek, I just merged the parquet-format
>> > change
>> > > > for
>> > > > > > > > ALP[1].
>> > > > > > > > > We
>> > > > > > > > > > >> >> plan to
>> > > > > > > > > > >> >> >>> > make additional editorial The remaining
>> items I
>> > > > know
>> > > > > of
>> > > > > > > are
>> > > > > > > > > > >> merging
>> > > > > > > > > > >> >> the
>> > > > > > > > > > >> >> >>> > examples from parquet-testing[2], and then
>> of
>> > > > course
>> > > > > > the
>> > > > > > > > > > various
>> > > > > > > > > > >> >> >>> > implementations
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>> > Thanks again everyone. This is a great step
>> > > forward
>> > > > > > > > > > >> >> >>> > Andrew
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>> > [1]:
>> > > > > https://github.com/apache/parquet-format/pull/557
>> > > > > > > > > > >> >> >>> > [2]:
>> > > > > > https://github.com/apache/parquet-testing/pull/100
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le
>> Dem <
>> > > > > > > > > > julien@apache.org
>> > > > > > > > > > >> >
>> > > > > > > > > > >> >> >>> wrote:
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>> > > It was also in my spam folder... :(
>> > > > > > > > > > >> >> >>> > > I've seen a bunch of apache list emails
>> go to
>> > > my
>> > > > > spam
>> > > > > > > > > > recently.
>> > > > > > > > > > >> >> >>> > >
>> > > > > > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell
>> > > Spitzer
>> > > > <
>> > > > > > > > > > >> >> >>> > > russell.spitzer@gmail.com>
>> > > > > > > > > > >> >> >>> > > wrote:
>> > > > > > > > > > >> >> >>> > >
>> > > > > > > > > > >> >> >>> > > > Yes, my hope was that my vote would
>> kick it
>> > > out
>> > > > > of
>> > > > > > > spam
>> > > > > > > > > but
>> > > > > > > > > > >> we
>> > > > > > > > > > >> >> >>> > definitely
>> > > > > > > > > > >> >> >>> > > > had two other votes that also went to
>> spam
>> > > for
>> > > > > me.
>> > > > > > > > > > >> >> >>> > > >
>> > > > > > > > > > >> >> >>> > > > For anyone looking the thread is here
>> > > > > > > > > > >> >> >>> > > >
>> > > > > > > > > > >> >>
>> > > > > > >
>> https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
>> > > > > > > > > > >> >> >>> > > >
>> > > > > > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah
>> > > > Kornfield
>> > > > > <
>> > > > > > > > > > >> >> >>> > emkornfield@gmail.com>
>> > > > > > > > > > >> >> >>> > > > wrote:
>> > > > > > > > > > >> >> >>> > > >
>> > > > > > > > > > >> >> >>> > > > > I've seen other's votes not go to
>> spam,
>> > so
>> > > > > > > hopefully
>> > > > > > > > > > people
>> > > > > > > > > > >> >> will
>> > > > > > > > > > >> >> >>> see
>> > > > > > > > > > >> >> >>> > it
>> > > > > > > > > > >> >> >>> > > > in
>> > > > > > > > > > >> >> >>> > > > > there inboxes (or see this thread and
>> > look
>> > > in
>> > > > > > there
>> > > > > > > > > > spam).
>> > > > > > > > > > >> >> >>> > > > >
>> > > > > > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM
>> PRATEEK
>> > > > GAUR <
>> > > > > > > > > > >> >> >>> prtkgaur@gmail.com>
>> > > > > > > > > > >> >> >>> > > > wrote:
>> > > > > > > > > > >> >> >>> > > > >
>> > > > > > > > > > >> >> >>> > > > > > Okay,
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > > > I sent out the voting email
>> yesterday
>> > and
>> > > > so
>> > > > > > far
>> > > > > > > > I've
>> > > > > > > > > > >> heard
>> > > > > > > > > > >> >> >>> from 3
>> > > > > > > > > > >> >> >>> > > > people
>> > > > > > > > > > >> >> >>> > > > > > that it ended up in their "spam
>> > folder".
>> > > > Dev
>> > > > > > VPN
>> > > > > > > to
>> > > > > > > > > be
>> > > > > > > > > > >> >> blamed
>> > > > > > > > > > >> >> >>> for
>> > > > > > > > > > >> >> >>> > > it?.
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > > > What's the protocol here?
>> > > > > > > > > > >> >> >>> > > > > > I let people hunt for the email in
>> > their
>> > > > spam
>> > > > > > > > folder
>> > > > > > > > > or
>> > > > > > > > > > >> send
>> > > > > > > > > > >> >> >>> out
>> > > > > > > > > > >> >> >>> > > > another
>> > > > > > > > > > >> >> >>> > > > > > one?
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > > > Best
>> > > > > > > > > > >> >> >>> > > > > > Prateek
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM
>> > PRATEEK
>> > > > > GAUR <
>> > > > > > > > > > >> >> >>> prtkgaur@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > wrote:
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > Hi team,
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > Vinoo has added the tests which
>> were
>> > > > > > requested
>> > > > > > > in
>> > > > > > > > > the
>> > > > > > > > > > >> last
>> > > > > > > > > > >> >> >>> round
>> > > > > > > > > > >> >> >>> > of
>> > > > > > > > > > >> >> >>> > > > > > review.
>> > > > > > > > > > >> >> >>> > > > > > > In his own words.
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > "
>> > > > > > > > > > >> >> >>> > > > > > > The extreme value tests Micah
>> wanted
>> > > are
>> > > > > done
>> > > > > > > and
>> > > > > > > > > > >> pushed.
>> > > > > > > > > > >> >> I
>> > > > > > > > > > >> >> >>> added
>> > > > > > > > > > >> >> >>> > > > > > coverage
>> > > > > > > > > > >> >> >>> > > > > > > for values that need the full FOR
>> bit
>> > > > width
>> > > > > > > after
>> > > > > > > > > the
>> > > > > > > > > > >> >> frame
>> > > > > > > > > > >> >> >>> of
>> > > > > > > > > > >> >> >>> > > > > reference
>> > > > > > > > > > >> >> >>> > > > > > is
>> > > > > > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where
>> the
>> > > > signed
>> > > > > > max
>> > > > > > > > > minus
>> > > > > > > > > > >> min
>> > > > > > > > > > >> >> >>> > > subtraction
>> > > > > > > > > > >> >> >>> > > > > > > overflows), 63-bit (the
>> non-overflow
>> > > > case),
>> > > > > > and
>> > > > > > > > > > 32-bit
>> > > > > > > > > > >> for
>> > > > > > > > > > >> >> >>> > floats.
>> > > > > > > > > > >> >> >>> > > > All
>> > > > > > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I
>> also
>> > > > > > verified
>> > > > > > > > them
>> > > > > > > > > > >> >> through
>> > > > > > > > > > >> >> >>> Arrow
>> > > > > > > > > > >> >> >>> > > C++
>> > > > > > > > > > >> >> >>> > > > > ALP
>> > > > > > > > > > >> >> >>> > > > > > > reader (the local build), so the
>> > > > > Java-written
>> > > > > > > > > extreme
>> > > > > > > > > > >> >> columns
>> > > > > > > > > > >> >> >>> > > decode
>> > > > > > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact
>> against
>> > the
>> > > > > > > expected
>> > > > > > > > > > >> values."
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > State of the PR (#3397):
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I
>> > > pulled
>> > > > > > > master
>> > > > > > > > in
>> > > > > > > > > > and
>> > > > > > > > > > >> >> >>> resolved
>> > > > > > > > > > >> >> >>> > > the
>> > > > > > > > > > >> >> >>> > > > > > >    conflicts).
>> > > > > > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads
>> > resolved.
>> > > > The
>> > > > > 3
>> > > > > > > > > > remaining
>> > > > > > > > > > >> are
>> > > > > > > > > > >> >> >>> > > > intentional:
>> > > > > > > > > > >> >> >>> > > > > > >    one deferred perf nit, one that
>> > > stays
>> > > > > open
>> > > > > > > > until
>> > > > > > > > > > >> >> >>> > parquet-format
>> > > > > > > > > > >> >> >>> > > > > ships
>> > > > > > > > > > >> >> >>> > > > > > ALP,
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > "
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > With this both the
>> > > > > > > > > > >> >> >>> > > > > > > 1) C++ PR :
>> > > > > > > > > > >> >> >>>
>> > https://github.com/apache/arrow/pull/48345/changes
>> > > > > > > > > > >> >> >>> > > > > > > 2) Java PR :
>> > > > > > > > > > >> >> >>>
>> https://github.com/apache/parquet-java/pull/3397
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > Are cross language tested and
>> range
>> > of
>> > > > test
>> > > > > > > > > > scenarios.
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > Best
>> > > > > > > > > > >> >> >>> > > > > > > Prateek
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM
>> > PRATEEK
>> > > > > GAUR
>> > > > > > <
>> > > > > > > > > > >> >> >>> prtkgaur@gmail.com
>> > > > > > > > > > >> >> >>> > >
>> > > > > > > > > > >> >> >>> > > > > wrote:
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > >> Thanks Matt,
>> > > > > > > > > > >> >> >>> > > > > > >>
>> > > > > > > > > > >> >> >>> > > > > > >> I'll be on it this week.
>> > > > > > > > > > >> >> >>> > > > > > >>
>> > > > > > > > > > >> >> >>> > > > > > >> Best
>> > > > > > > > > > >> >> >>> > > > > > >> Prateek
>> > > > > > > > > > >> >> >>> > > > > > >>
>> > > > > > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM
>> Matt
>> > > > > Topol <
>> > > > > > > > > > >> >> >>> > > zotthewizard@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> There is also the Go
>> implementation
>> > > > > > submitted
>> > > > > > > > by
>> > > > > > > > > > >> Arnav (
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > https://github.com/apache/arrow-go/pull/704)
>> > > > > > > > > which
>> > > > > > > > > > >> is
>> > > > > > > > > > >> >> >>> waiting
>> > > > > > > > > > >> >> >>> > > for
>> > > > > > > > > > >> >> >>> > > > > > >>> updates.
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it
>> didn't
>> > > get
>> > > > > lost
>> > > > > > > > here.
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> --Matt
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM
>> > > > PRATEEK
>> > > > > > > GAUR <
>> > > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > Hi all,
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > I'd like to share a status
>> update
>> > > on
>> > > > > the
>> > > > > > > ALP
>> > > > > > > > > > >> encoding
>> > > > > > > > > > >> >> >>> effort
>> > > > > > > > > > >> >> >>> > > and
>> > > > > > > > > > >> >> >>> > > > > get
>> > > > > > > > > > >> >> >>> > > > > > a
>> > > > > > > > > > >> >> >>> > > > > > >>> feel
>> > > > > > > > > > >> >> >>> > > > > > >>> > from the community before
>> > starting
>> > > a
>> > > > > > formal
>> > > > > > > > > vote.
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > We now have the specification
>> > plus
>> > > > > > > > > > implementations
>> > > > > > > > > > >> in
>> > > > > > > > > > >> >> >>> both
>> > > > > > > > > > >> >> >>> > > > > languages:
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> >     - Spec:
>> > > > > > > >  apache/parquet-format#557 —
>> > > > > > > > > > >> GH-533
>> > > > > > > > > > >> >> >>> Add
>> > > > > > > > > > >> >> >>> > ALP
>> > > > > > > > > > >> >> >>> > > > > > encoding
>> > > > > > > > > > >> >> >>> > > > > > >>> > specification
>> > > > > > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):
>> > > > apache/arrow#48345
>> > > > > —
>> > > > > > > > > GH-48701
>> > > > > > > > > > >> >> >>> > > [C++][Parquet]
>> > > > > > > > > > >> >> >>> > > > > Add
>> > > > > > > > > > >> >> >>> > > > > > >>> ALPpd
>> > > > > > > > > > >> >> >>> > > > > > >>> > encoding
>> > > > > > > > > > >> >> >>> > > > > > >>> >     - Java:
>> > > > > > >  apache/parquet-java#3397
>> > > > > > > > —
>> > > > > > > > > > >> Parquet
>> > > > > > > > > > >> >> >>> Java
>> > > > > > > > > > >> >> >>> > ALP
>> > > > > > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > Current state:
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation
>> has
>> > > been
>> > > > > > > through
>> > > > > > > > > 3-4
>> > > > > > > > > > >> >> rounds
>> > > > > > > > > > >> >> >>> of
>> > > > > > > > > > >> >> >>> > > > review.
>> > > > > > > > > > >> >> >>> > > > > > >>> >     - The Java implementation
>> has
>> > > > been
>> > > > > > > > tracking
>> > > > > > > > > > >> well
>> > > > > > > > > > >> >> and
>> > > > > > > > > > >> >> >>> has
>> > > > > > > > > > >> >> >>> > > had
>> > > > > > > > > > >> >> >>> > > > > > >>> initial
>> > > > > > > > > > >> >> >>> > > > > > >>> >       reviews from
>> contributors,
>> > > with
>> > > > > no
>> > > > > > > > major
>> > > > > > > > > > >> >> remaining
>> > > > > > > > > > >> >> >>> > > issues.
>> > > > > > > > > > >> >> >>> > > > > > >>> >     - Cross-language
>> > compatibility
>> > > > > tests
>> > > > > > > are
>> > > > > > > > > > >> passing:
>> > > > > > > > > > >> >> the
>> > > > > > > > > > >> >> >>> > Arrow
>> > > > > > > > > > >> >> >>> > > > C++
>> > > > > > > > > > >> >> >>> > > > > > >>> decoder
>> > > > > > > > > > >> >> >>> > > > > > >>> >       reads Java-written data
>> > > > > bit-exactly
>> > > > > > > > > across
>> > > > > > > > > > >> >> ~1.56M
>> > > > > > > > > > >> >> >>> > values
>> > > > > > > > > > >> >> >>> > > > and
>> > > > > > > > > > >> >> >>> > > > > 18
>> > > > > > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1
>> and
>> > V2
>> > > > > pages,
>> > > > > > > > > > multiple
>> > > > > > > > > > >> >> vector
>> > > > > > > > > > >> >> >>> > > sizes,
>> > > > > > > > > > >> >> >>> > > > > and
>> > > > > > > > > > >> >> >>> > > > > > >>> > several
>> > > > > > > > > > >> >> >>> > > > > > >>> >       real datasets — zero
>> > > > mismatches.
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we
>> will
>> > > be
>> > > > > > adding
>> > > > > > > > > > >> coverage
>> > > > > > > > > > >> >> for
>> > > > > > > > > > >> >> >>> > > extreme
>> > > > > > > > > > >> >> >>> > > > > > values
>> > > > > > > > > > >> >> >>> > > > > > >>> > (those requiring
>> > > > > > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is
>> applied)
>> > > > > before
>> > > > > > we
>> > > > > > > > > > close a
>> > > > > > > > > > >> >> vote.
>> > > > > > > > > > >> >> >>> > We'll
>> > > > > > > > > > >> >> >>> > > > aim
>> > > > > > > > > > >> >> >>> > > > > > to
>> > > > > > > > > > >> >> >>> > > > > > >>> get
>> > > > > > > > > > >> >> >>> > > > > > >>> > that
>> > > > > > > > > > >> >> >>> > > > > > >>> >  done in parallel.
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > Plan: unless there are
>> > objections,
>> > > I
>> > > > > > intend
>> > > > > > > > to
>> > > > > > > > > > >> start a
>> > > > > > > > > > >> >> >>> vote
>> > > > > > > > > > >> >> >>> > at
>> > > > > > > > > > >> >> >>> > > > the
>> > > > > > > > > > >> >> >>> > > > > > end
>> > > > > > > > > > >> >> >>> > > > > > >>> of
>> > > > > > > > > > >> >> >>> > > > > > >>> > this week/early
>> > > > > > > > > > >> >> >>> > > > > > >>> > next week.
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > Thanks
>> > > > > > > > > > >> >> >>> > > > > > >>> > Prateek
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM
>> > > > PRATEEK
>> > > > > > > GAUR <
>> > > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > > Hi Team,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some
>> > > updates
>> > > > > on
>> > > > > > > ALP.
>> > > > > > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4
>> > rounds
>> > > of
>> > > > > > > review
>> > > > > > > > > for
>> > > > > > > > > > >> the
>> > > > > > > > > > >> >> c++
>> > > > > > > > > > >> >> >>> PR :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > https://github.com/apache/arrow/pull/48345
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > > For the Java implementation
>> > Vinoo
>> > > > has
>> > > > > > > been
>> > > > > > > > > > >> working
>> > > > > > > > > > >> >> on
>> > > > > > > > > > >> >> >>> > > following
>> > > > > > > > > > >> >> >>> > > > > PR
>> > > > > > > > > > >> >> >>> > > > > > :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > https://github.com/apache/parquet-java/pull/3397
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > > Best
>> > > > > > > > > > >> >> >>> > > > > > >>> > > Prateek
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at
>> 1:50 PM
>> > > > Micah
>> > > > > > > > > Kornfield
>> > > > > > > > > > <
>> > > > > > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> > > wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question
>> > was
>> > > > > > already
>> > > > > > > > > asked,
>> > > > > > > > > > >> but
>> > > > > > > > > > >> >> >>> should
>> > > > > > > > > > >> >> >>> > we
>> > > > > > > > > > >> >> >>> > > > > care
>> > > > > > > > > > >> >> >>> > > > > > >>> about
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can
>> FLOAT +
>> > > ALP
>> > > > > be
>> > > > > > > more
>> > > > > > > > > > >> >> efficient
>> > > > > > > > > > >> >> >>> than
>> > > > > > > > > > >> >> >>> > > > > FLOAT16
>> > > > > > > > > > >> >> >>> > > > > > +
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4
>> for
>> > > > > example?
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we
>> could
>> > > defer
>> > > > > it
>> > > > > > > for
>> > > > > > > > > the
>> > > > > > > > > > >> >> >>> following
>> > > > > > > > > > >> >> >>> > > > reasons:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there
>> are a
>> > > lot
>> > > > > of
>> > > > > > > easy
>> > > > > > > > > > >> >> reference
>> > > > > > > > > > >> >> >>> > > datasets
>> > > > > > > > > > >> >> >>> > > > to
>> > > > > > > > > > >> >> >>> > > > > > >>> test
>> > > > > > > > > > >> >> >>> > > > > > >>> > its
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does
>> look
>> > > like
>> > > > > > there
>> > > > > > > > > might
>> > > > > > > > > > be
>> > > > > > > > > > >> >> one
>> > > > > > > > > > >> >> >>> or
>> > > > > > > > > > >> >> >>> > two
>> > > > > > > > > > >> >> >>> > > on
>> > > > > > > > > > >> >> >>> > > > > > >>> > huggingface
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> (e.g.
>> > > > > > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
>> > > > > > > > > > >> >> >>> ).
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that
>> > float
>> > > 16
>> > > > > was
>> > > > > > > > more
>> > > > > > > > > > >> likely
>> > > > > > > > > > >> >> >>> used
>> > > > > > > > > > >> >> >>> > for
>> > > > > > > > > > >> >> >>> > > > > values
>> > > > > > > > > > >> >> >>> > > > > > >>> that
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce
>> to
>> > > > > decimal
>> > > > > > > > > values.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an
>> > > > > extension
>> > > > > > > > later
>> > > > > > > > > if
>> > > > > > > > > > >> >> needed.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> Cheers,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> Micah
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at
>> 1:40 PM
>> > > > > Antoine
>> > > > > > > > > Pitrou
>> > > > > > > > > > <
>> > > > > > > > > > >> >> >>> > > > > antoine@python.org
>> > > > > > > > > > >> >> >>> > > > > > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Hello,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question
>> > was
>> > > > > > already
>> > > > > > > > > asked,
>> > > > > > > > > > >> but
>> > > > > > > > > > >> >> >>> should
>> > > > > > > > > > >> >> >>> > we
>> > > > > > > > > > >> >> >>> > > > > care
>> > > > > > > > > > >> >> >>> > > > > > >>> about
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can
>> FLOAT +
>> > > ALP
>> > > > > be
>> > > > > > > more
>> > > > > > > > > > >> >> efficient
>> > > > > > > > > > >> >> >>> than
>> > > > > > > > > > >> >> >>> > > > > FLOAT16
>> > > > > > > > > > >> >> >>> > > > > > +
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4
>> for
>> > > > > example?
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Regards
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10,
>> > PRATEEK
>> > > > > GAUR
>> > > > > > a
>> > > > > > > > > écrit
>> > > > > > > > > > :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah
>> > for
>> > > > > review
>> > > > > > > > > > feedback
>> > > > > > > > > > >> on
>> > > > > > > > > > >> >> >>> the two
>> > > > > > > > > > >> >> >>> > > > PR's
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> https://github.com/apache/arrow/pull/48345/changes
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format
>> repo)
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> https://github.com/apache/parquet-format/pull/557
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all
>> > > (unless I
>> > > > > > > missed
>> > > > > > > > > > >> >> something)
>> > > > > > > > > > >> >> >>> > > comments
>> > > > > > > > > > >> >> >>> > > > on
>> > > > > > > > > > >> >> >>> > > > > > >>> the two
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > PR's.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Best
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at
>> > > > 1:08 PM
>> > > > > > > > PRATEEK
>> > > > > > > > > > >> GAUR <
>> > > > > > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and
>> Micah.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of
>> feedback
>> > on
>> > > > at
>> > > > > > > least
>> > > > > > > > > the
>> > > > > > > > > > >> >> >>> > > implementations`
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have
>> > already
>> > > > > > started
>> > > > > > > > > > >> addressing
>> > > > > > > > > > >> >> the
>> > > > > > > > > > >> >> >>> > > > > feedback, I
>> > > > > > > > > > >> >> >>> > > > > > >>> > should
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> be
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> done with that
>> > > > Monday/Tuesday.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has
>> > been
>> > > > > making
>> > > > > > > > good
>> > > > > > > > > > >> >> progress
>> > > > > > > > > > >> >> >>> on
>> > > > > > > > > > >> >> >>> > the
>> > > > > > > > > > >> >> >>> > > > Java
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > implementation.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Best
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026
>> at
>> > > > > 12:55 PM
>> > > > > > > > Andrew
>> > > > > > > > > > >> Lamb <
>> > > > > > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for
>> > the
>> > > > > > > > > clarification
>> > > > > > > > > > >> -- I
>> > > > > > > > > > >> >> >>> will
>> > > > > > > > > > >> >> >>> > try
>> > > > > > > > > > >> >> >>> > > > and
>> > > > > > > > > > >> >> >>> > > > > > look
>> > > > > > > > > > >> >> >>> > > > > > >>> > into
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> the
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
>> > > > > > > implementation[1]
>> > > > > > > > in
>> > > > > > > > > > >> this
>> > > > > > > > > > >> >> next
>> > > > > > > > > > >> >> >>> > week
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
>> > > > > > > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026
>> at
>> > > > > 12:01 PM
>> > > > > > > > Micah
>> > > > > > > > > > >> >> >>> Kornfield <
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a
>> fair
>> > > > > amount
>> > > > > > of
>> > > > > > > > > > >> feedback
>> > > > > > > > > > >> >> on
>> > > > > > > > > > >> >> >>> at
>> > > > > > > > > > >> >> >>> > > least
>> > > > > > > > > > >> >> >>> > > > > the
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations,
>> > > typically
>> > > > I
>> > > > > > > think
>> > > > > > > > > > we've
>> > > > > > > > > > >> >> waited
>> > > > > > > > > > >> >> >>> > till
>> > > > > > > > > > >> >> >>> > > > they
>> > > > > > > > > > >> >> >>> > > > > > are
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> close to
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a
>> > final
>> > > > > vote.
>> > > > > > > > > > >> Otherwise I
>> > > > > > > > > > >> >> >>> agree
>> > > > > > > > > > >> >> >>> > we
>> > > > > > > > > > >> >> >>> > > > are
>> > > > > > > > > > >> >> >>> > > > > > very
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> close.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April
>> 25,
>> > > > 2026,
>> > > > > > > Andrew
>> > > > > > > > > > Lamb
>> > > > > > > > > > >> <
>> > > > > > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this
>> > > content
>> > > > it
>> > > > > > > looks
>> > > > > > > > > to
>> > > > > > > > > > me
>> > > > > > > > > > >> >> like
>> > > > > > > > > > >> >> >>> we
>> > > > > > > > > > >> >> >>> > are
>> > > > > > > > > > >> >> >>> > > > > ready
>> > > > > > > > > > >> >> >>> > > > > > >>> to
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> start a
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly
>> > > accept
>> > > > > ALP
>> > > > > > > into
>> > > > > > > > > > >> Parquet
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know
>> of a
>> > > > reason
>> > > > > > we
>> > > > > > > > > should
>> > > > > > > > > > >> >> >>> postpone it
>> > > > > > > > > > >> >> >>> > > for
>> > > > > > > > > > >> >> >>> > > > > > >>> longer?
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone
>> needs
>> > > some
>> > > > > > more
>> > > > > > > > time
>> > > > > > > > > > to
>> > > > > > > > > > >> >> >>> review?
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22,
>> 2026
>> > at
>> > > > > > 1:00 PM
>> > > > > > > > > > PRATEEK
>> > > > > > > > > > >> >> GAUR <
>> > > > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is
>> > doing
>> > > > > well.
>> > > > > > I
>> > > > > > > > got
>> > > > > > > > > a
>> > > > > > > > > > >> >> chance
>> > > > > > > > > > >> >> >>> to
>> > > > > > > > > > >> >> >>> > work
>> > > > > > > > > > >> >> >>> > > > > > >>> through all
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> the
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback
>> > and
>> > > > > update
>> > > > > > > the
>> > > > > > > > > > spec
>> > > > > > > > > > >> >> doc.
>> > > > > > > > > > >> >> >>> Here
>> > > > > > > > > > >> >> >>> > > are
>> > > > > > > > > > >> >> >>> > > > > the
>> > > > > > > > > > >> >> >>> > > > > > >>> new
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > artifacts
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > >
>> > > > > > > > > > >> >> >>> > > >
>> > > > > > > > > > >> >> >>> > >
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>>
>> > > > > > > > > > >> >>
>> > > > > > > > > > >>
>> > > > > > > > > >
>> > > > > > > > >
>> > > > > > > >
>> > > > > > >
>> > > > > >
>> > > > > https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-
>> > > > 3fPtD_aWt/edit
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document
>> in
>> > > > parquet
>> > > > > > > > format
>> > > > > > > > > > >> repo :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> >
>> > > https://github.com/apache/parquet-format/pull/557
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp
>> implementation
>> > > in
>> > > > > > arrow
>> > > > > > > > c++
>> > > > > > > > > > >> repo :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> >
>> > > https://github.com/apache/arrow/pull/48345/changes
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp
>> implementation
>> > > in
>> > > > > > > > > parquet-java
>> > > > > > > > > > >> >> repo :
>> > > > > > > > > > >> >> >>> Work
>> > > > > > > > > > >> >> >>> > > for
>> > > > > > > > > > >> >> >>> > > > > > >>> Vinoo and
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Julien
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> >
>> > https://github.com/apache/parquet-java/pull/3397
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test
>> and
>> > > > > > > benchmarking
>> > > > > > > > > > >> >> artifacts in
>> > > > > > > > > > >> >> >>> > > > > > >>> parquet-testing
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> repo :
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
>> > > > > > > > > > >> >> >>> >
>> > > https://github.com/apache/parquet-testing/pull/100
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>> > > > > > 9:49 AM
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>> <
>> > > > > > > > > > >> emkornfield@gmail.com>
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>> > 2026
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>> > > > > > > 7:28 PM
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>> for
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>> > resolving
>> > > > all
>> > > > > > > > > remaining
>> > > > > > > > > > >> open
>> > > > > > > > > > >> >> >>> > comments
>> > > > > > > > > > >> >> >>> > > > on
>> > > > > > > > > > >> >> >>> > > > > > the
>> > > > > > > > > > >> >> >>> > > > > > >>> spec
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> this
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> week.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10,
>> > 2026
>> > > > at
>> > > > > > > > 3:37 AM
>> > > > > > > > > > >> Steve
>> > > > > > > > > > >> >> >>> > Loughran <
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
>> > stevel@cloudera.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb
>> > 2026
>> > > at
>> > > > > > > 18:12,
>> > > > > > > > > > Micah
>> > > > > > > > > > >> >> >>> Kornfield
>> > > > > > > > > > >> >> >>> > <
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
>> > > emkornfield@gmail.com>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like
>> > the
>> > > > > actual
>> > > > > > > > issue
>> > > > > > > > > > >> >> >>> described for
>> > > > > > > > > > >> >> >>> > > ORC
>> > > > > > > > > > >> >> >>> > > > > in
>> > > > > > > > > > >> >> >>> > > > > > >>> the
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> paper
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
>> > > > > > sub-encodings
>> > > > > > > > in
>> > > > > > > > > a
>> > > > > > > > > > >> >> batch.
>> > > > > > > > > > >> >> >>> This
>> > > > > > > > > > >> >> >>> > > is
>> > > > > > > > > > >> >> >>> > > > > > >>> different
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> then
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here
>> > > where
>> > > > > > there
>> > > > > > > is
>> > > > > > > > > > still
>> > > > > > > > > > >> >> fixed
>> > > > > > > > > > >> >> >>> > > > encoding
>> > > > > > > > > > >> >> >>> > > > > > per
>> > > > > > > > > > >> >> >>> > > > > > >>> page
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> in
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given
>> reasonably
>> > > > sized
>> > > > > > > > pages I
>> > > > > > > > > > >> don't
>> > > > > > > > > > >> >> >>> think
>> > > > > > > > > > >> >> >>> > > > branch
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction
>> > should
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for
>> > new
>> > > > > > > encodings.
>> > > > > > > > > I
>> > > > > > > > > > >> agree
>> > > > > > > > > > >> >> >>> that
>> > > > > > > > > > >> >> >>> > we
>> > > > > > > > > > >> >> >>> > > > > should
>> > > > > > > > > > >> >> >>> > > > > > >>> be
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for
>> > adding
>> > > > new
>> > > > > > > > > > encodings.
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
>> > > > > > > > > > >> >> >>> > > > > > >>> > >>
>> > > > > > > > > > >> >> >>> > > > > > >>> > >
>> > > > > > > > > > >> >> >>> > > > > > >>> >
>> > > > > > > > > > >> >> >>> > > > > > >>>
>> > > > > > > > > > >> >> >>> > > > > > >>
>> > > > > > > > > > >> >> >>> > > > > >
>> > > > > > > > > > >> >> >>> > > > >
>> > > > > > > > > > >> >> >>> > > >
>> > > > > > > > > > >> >> >>> > >
>> > > > > > > > > > >> >> >>> >
>> > > > > > > > > > >> >> >>>
>> > > > > > > > > > >> >> >>
>> > > > > > > > > > >> >>
>> > > > > > > > > > >> >
>> > > > > > > > > > >>
>> > > > > > > > > > >
>> > > > > > > > > >
>> > > > > > > > >
>> > > > > > > >
>> > > > > > >
>> > > > > >
>> > > > >
>> > > >
>> > >
>> >
>>
>

Re: [Parquet] ALP Encoding for Floating point data

[Gang Wu <us...@gmail.com>]

Thanks Gunnar for sharing this!

I think the encoder approach used by Hardwood looks more similar to the ALP
paper where all 102,400 values are buffered to decide best presets and then
encode every vector based on those presets.

I'm trying to improve the ALP implementations on the Parquet C++ side:
https://github.com/apache/arrow/pull/55449. So I'm really interested
if you have any document on performance comparison among different
implementations.

Thanks!
Gang

On Thu, Nov 12, 2026 at 6:50 PM Gunnar Morling via dev <
dev@parquet.apache.org> wrote:

> Hey all,
>
> We've added ALP encoding and decoding support to Hardwood too [1], [2].
> Interop with parquet-java's implementation looks good: Hardwood decodes
> pages written by parquet-java's ALP writer bit-exactly and vice versa.
>
> Perhaps interesting: on the encoder side, we build the preset of a column
> chunk from eight sample vectors distributed across the entire chunk (easy
> in our case, as Hardwood's writer buffers whole chunks), whereas, IIUC,
> parquet-java only samples within the first ~110K values of a chunk.
> Depending on the data distribution, this can yield a more efficient
> encoding, for instance when a high-cardinality column changes character
> midway, e.g. moving from two to four decimal places (about 2.8× smaller in
> a synthetic test with 1M doubles).
>
> Best,
>
> --Gunnar
>
> [1] https://github.com/hardwood-hq/hardwood/pull/1496
> [2] https://github.com/hardwood-hq/hardwood/pull/1769
>
>
> On Thu, 12 Nov 2026 at 07:01, PRATEEK GAUR <pr...@gmail.com> wrote:
>
> > Thanks everyone!
> >
> > On Mon, Nov 9, 2026 at 11:58 AM Vinoo Ganesh <vi...@gmail.com>
> > wrote:
> >
> > > Thanks everyone!
> > >
> > > Thanks,
> > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > >
> > > <Vi...@gmail.com>
> > >
> > >
> > > On Mon, Nov 9, 2026 at 2:49 PM Andrew Lamb <an...@gmail.com>
> > wrote:
> > >
> > > > The Java implementation was just merged[1]!
> > > >
> > > > Thank you Gang, Vinoo, Prateek and everyone who helped push that one
> > > along
> > > >
> > > > Andrew
> > > >
> > > > [1]:
> > https://github.com/apache/parquet-java/pull/3397#event-35545451335
> > > >
> > > > On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <pr...@gmail.com>
> > > wrote:
> > > >
> > > > > Hi team,
> > > > >
> > > > > Quick update re: the C++ implementation.
> > > > > Thanks to all the reviewers, we merged the C++ implementation
> today.
> > > > > There are a few follow-up items that I'll address in a subsequent
> PR.
> > > > >
> > > > > Thanks
> > > > > Prateek
> > > > >
> > > > > On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <
> vinoo.ganesh@gmail.com
> > >
> > > > > wrote:
> > > > >
> > > > > > Quick update re: the Java impl. Thanks for the feedback, on
> > > > > > https://github.com/apache/parquet-java/pull/3397, Russel! I
> pulled
> > > > > > https://github.com/apache/parquet-java/pull/3791 into its own PR
> > > > (thanks
> > > > > > for the quick approval too, Gang). Assuming no objections, I
> think
> > we
> > > > can
> > > > > > merge #3791, and then go ahead of #3397.
> > > > > >
> > > > > > Thanks,
> > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > > > >
> > > > > > <Vi...@gmail.com>
> > > > > >
> > > > > >
> > > > > > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <prtkgaur@gmail.com
> >
> > > > wrote:
> > > > > >
> > > > > > > [Rust] Awesome thanks Andrew, Kostas and Devin.
> > > > > > > [Java] Thanks Gang for the feedback on Java PR.
> > > > > > > [C++] Thanks Gang for another round of feedback on the C++ one.
> > > > > > > [Go] Arnav and I will be working on the golang impl this week.
> > > > > > >
> > > > > > > This is great progress all around.
> > > > > > >
> > > > > > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <
> > > vinoo.ganesh@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Thanks all - I'm addressing Gang's comments on
> > > > > > > > https://github.com/apache/parquet-java/pull/3397 now, so
> > > hopefully
> > > > > > well
> > > > > > > > also be in a good state for merging the java implementation
> > soon.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > > > > > >
> > > > > > > > <Vi...@gmail.com>
> > > > > > > >
> > > > > > > >
> > > > > > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <
> > > andrewlamb11@gmail.com
> > > > >
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > > We just merged the Rust implementation[1] from Kosta and
> > Devan.
> > > > > With
> > > > > > > the
> > > > > > > > > imminent release of Parquet Format 2.14.0 I think we'll be
> > well
> > > > on
> > > > > > our
> > > > > > > > way.
> > > > > > > > >
> > > > > > > > > Thanks again for pushing this along,
> > > > > > > > > Andrew
> > > > > > > > >
> > > > > > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> > > > > > > > >
> > > > > > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <
> > > prtkgaur@gmail.com>
> > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi team,
> > > > > > > > > >
> > > > > > > > > > Thanks Micah for multiple rounds of review and thanks
> Gang
> > > for
> > > > > > > taking a
> > > > > > > > > > look at the PR and giving feedback. I've addressed all
> > > comments
> > > > > in
> > > > > > > the
> > > > > > > > > PR.
> > > > > > > > > > Looking forward to the next round of feedback (or
> > approval).
> > > > > Would
> > > > > > > like
> > > > > > > > > to
> > > > > > > > > > get it in soon.
> > > > > > > > > >
> > > > > > > > > > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > >
> > > > > > > > > > With this done and after talking to Arnav, I plan to
> spend
> > > some
> > > > > > time
> > > > > > > on
> > > > > > > > > the
> > > > > > > > > > ALP implementation in the arrow-go repository helping
> > spread
> > > > the
> > > > > > > > support
> > > > > > > > > to
> > > > > > > > > > more languages.
> > > > > > > > > >
> > > > > > > > > > Best
> > > > > > > > > > Prateek
> > > > > > > > > >
> > > > > > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <
> > > > prtkgaur@gmail.com
> > > > > >
> > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Thanks Divjot for bringing it up.
> > > > > > > > > > >
> > > > > > > > > > > I was under the same impression as Russell and Andrew
> > that
> > > > we'd
> > > > > > > have
> > > > > > > > it
> > > > > > > > > > > flag gated.
> > > > > > > > > > > With the new versioning proposal 'preview' might be a
> > good
> > > > tag
> > > > > > for
> > > > > > > > it.
> > > > > > > > > > >
> > > > > > > > > > > Best
> > > > > > > > > > > Prateek
> > > > > > > > > > >
> > > > > > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> > > > > > > andrewlamb11@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1]
> > > (using a
> > > > > > > comment
> > > > > > > > > in
> > > > > > > > > > >> the
> > > > > > > > > > >> spec section).
> > > > > > > > > > >>
> > > > > > > > > > >> Russel: That is my understanding as well.
> > > > > > > > > > >>
> > > > > > > > > > >> Hopefully we are able to formalize the versioning
> > process
> > > > > > shortly
> > > > > > > so
> > > > > > > > > we
> > > > > > > > > > >> can
> > > > > > > > > > >> formalize the notion of "preview"
> > > > > > > > > > >>
> > > > > > > > > > >> Andrew
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> [1]:
> https://github.com/apache/parquet-format/pull/604
> > > > > > > > > > >>
> > > > > > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> > > > > > > > > > >> russell.spitzer@gmail.com>
> > > > > > > > > > >> wrote:
> > > > > > > > > > >>
> > > > > > > > > > >> > I thought we had agreed it would be merged, and
> > features
> > > > > like
> > > > > > > this
> > > > > > > > > > would
> > > > > > > > > > >> > be feature flag gated. So a V-Old writer could
> always
> > > opt
> > > > in
> > > > > > to
> > > > > > > > > using
> > > > > > > > > > >> this
> > > > > > > > > > >> > encoding but that must be a conscious effort if you
> > are
> > > > not
> > > > > > > using
> > > > > > > > > > VNext
> > > > > > > > > > >> of
> > > > > > > > > > >> > Parquet. If you are on V-Next the writer can choose
> to
> > > use
> > > > > ALP
> > > > > > > > > > whenever
> > > > > > > > > > >> it
> > > > > > > > > > >> > likes without user intervention.
> > > > > > > > > > >> >
> > > > > > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via
> dev <
> > > > > > > > > > >> > dev@parquet.apache.org> wrote:
> > > > > > > > > > >> >
> > > > > > > > > > >> >> Yes, that’s my understanding as well. However, as
> you
> > > > > noted,
> > > > > > > the
> > > > > > > > > > >> >> versioning
> > > > > > > > > > >> >> discussion is still in early stages and hasn’t
> > > prescribed
> > > > > > > > concrete
> > > > > > > > > > >> >> mechanisms yet. If ALP goes into parquet-format
> > 2.14.0,
> > > > > > there’s
> > > > > > > > no
> > > > > > > > > > >> >> indication that it’s in preview or that writers
> > > shouldn’t
> > > > > use
> > > > > > > it
> > > > > > > > by
> > > > > > > > > > >> >> default
> > > > > > > > > > >> >> yet. Given that we’ve held off on merging other
> > > > > incompatible
> > > > > > > > > changes
> > > > > > > > > > >> (e.g
> > > > > > > > > > >> >> removal of path_in_schema) until the versioning
> > > > discussion
> > > > > > > > closes,
> > > > > > > > > my
> > > > > > > > > > >> >> preference would be to leave ALP un-merged for the
> > time
> > > > > being
> > > > > > > as
> > > > > > > > > > well.
> > > > > > > > > > >> >>
> > > > > > > > > > >> >> — Div
> > > > > > > > > > >> >>
> > > > > > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> > > > > > > > andrewlamb11@gmail.com>
> > > > > > > > > > >> wrote:
> > > > > > > > > > >> >>
> > > > > > > > > > >> >> > After re-reading Julien's Versioning Proposal, my
> > > > > > > understanding
> > > > > > > > > is
> > > > > > > > > > >> that
> > > > > > > > > > >> >> if
> > > > > > > > > > >> >> > we adopt that system, we will somehow mark ALP in
> > > > > "Preview"
> > > > > > > in
> > > > > > > > > > >> >> > parquet-format for release Version 3.
> > > > > > > > > > >> >> >
> > > > > > > > > > >> >> > The versioning document doesn't seem to proscribe
> > the
> > > > > > > > particular
> > > > > > > > > > >> method
> > > > > > > > > > >> >> > for annotating "preview" features -- I think
> > clearly
> > > > > > marking
> > > > > > > > them
> > > > > > > > > > as
> > > > > > > > > > >> >> such
> > > > > > > > > > >> >> > in parquet.thrift as well as reflecting that on
> the
> > > > > > > > > > >> >> >
> > > https://parquet.apache.org/docs/file-format/versions/
> > > > > page
> > > > > > > > > somehow
> > > > > > > > > > >> >> would
> > > > > > > > > > >> >> > be adequate.
> > > > > > > > > > >> >> >
> > > > > > > > > > >> >> > Andrew
> > > > > > > > > > >> >> >
> > > > > > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> > > > > > > > > > andrewlamb11@gmail.com
> > > > > > > > > > >> >
> > > > > > > > > > >> >> > wrote:
> > > > > > > > > > >> >> >
> > > > > > > > > > >> >> >> In my mind ALP is in the same position as other
> > > > > encodings
> > > > > > > that
> > > > > > > > > > were
> > > > > > > > > > >> >> added
> > > > > > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non
> > > > floating
> > > > > > > point
> > > > > > > > > > types)
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> That is to say it will be available in the
> latest
> > > open
> > > > > > > source
> > > > > > > > > > >> writers
> > > > > > > > > > >> >> and
> > > > > > > > > > >> >> >> readers, but realistically not widely used in
> the
> > > > > > ecosystem
> > > > > > > > > where
> > > > > > > > > > >> >> >> compatibility is a concern (a large part)
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> I view Julian's work[2][3] to gather consensus
> on
> > > how
> > > > to
> > > > > > > name
> > > > > > > > > > >> >> >> combinations of features (e.g. "versions") as
> the
> > > > > > mechanism
> > > > > > > by
> > > > > > > > > > >> which we
> > > > > > > > > > >> >> >> will accelerate the adoption of this change
> (along
> > > > with
> > > > > > > other
> > > > > > > > > > >> forward
> > > > > > > > > > >> >> >> incompatible changes) across the ecosystem.
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> > Will we exclude this change when cutting
> > > > > parquet-format
> > > > > > > > > v2.14.0?
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> No I don't think so -- I would expect it to go
> out
> > > in
> > > > > the
> > > > > > > next
> > > > > > > > > > >> >> >> parquet-format version as do other changes in
> the
> > > > spec.
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> Andrew
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> [1]:
> > > > > > https://parquet.apache.org/docs/file-format/versions/
> > > > > > > > > > >> >> >> [2]:
> > > > > > > > > > >>
> > > > > > https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> > > > > > > > > > >> >> >> [3]:
> > > > > > > > > > >>
> > > > > > https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora via
> > > dev <
> > > > > > > > > > >> >> >> dev@parquet.apache.org> wrote:
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >> >>> Hi Andrew,
> > > > > > > > > > >> >> >>>
> > > > > > > > > > >> >> >>> How does this interact with the ongoing
> > versioning
> > > > > > > > discussion?
> > > > > > > > > > >> Given
> > > > > > > > > > >> >> that
> > > > > > > > > > >> >> >>> new encodings are not forward compatible, I
> would
> > > > > assume
> > > > > > > ALP
> > > > > > > > is
> > > > > > > > > > >> >> included
> > > > > > > > > > >> >> >>> in
> > > > > > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to me
> > how
> > > > > that
> > > > > > > > works
> > > > > > > > > if
> > > > > > > > > > >> it's
> > > > > > > > > > >> >> >>> merged to the parquet-format master branch now.
> > > Will
> > > > we
> > > > > > > > exclude
> > > > > > > > > > >> this
> > > > > > > > > > >> >> >>> change
> > > > > > > > > > >> >> >>> when cutting parquet-format v2.14.0?
> > > > > > > > > > >> >> >>>
> > > > > > > > > > >> >> >>> -- Div
> > > > > > > > > > >> >> >>>
> > > > > > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
> > > > > > > > > > >> andrewlamb11@gmail.com>
> > > > > > > > > > >> >> >>> wrote:
> > > > > > > > > > >> >> >>>
> > > > > > > > > > >> >> >>> > Hello,
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>> > As an update, thanks to the epic work from
> many
> > > > > > > > contributors,
> > > > > > > > > > >> >> >>> especially
> > > > > > > > > > >> >> >>> > Prateek, I just merged the parquet-format
> > change
> > > > for
> > > > > > > > ALP[1].
> > > > > > > > > We
> > > > > > > > > > >> >> plan to
> > > > > > > > > > >> >> >>> > make additional editorial The remaining
> items I
> > > > know
> > > > > of
> > > > > > > are
> > > > > > > > > > >> merging
> > > > > > > > > > >> >> the
> > > > > > > > > > >> >> >>> > examples from parquet-testing[2], and then of
> > > > course
> > > > > > the
> > > > > > > > > > various
> > > > > > > > > > >> >> >>> > implementations
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>> > Thanks again everyone. This is a great step
> > > forward
> > > > > > > > > > >> >> >>> > Andrew
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>> > [1]:
> > > > > https://github.com/apache/parquet-format/pull/557
> > > > > > > > > > >> >> >>> > [2]:
> > > > > > https://github.com/apache/parquet-testing/pull/100
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le
> Dem <
> > > > > > > > > > julien@apache.org
> > > > > > > > > > >> >
> > > > > > > > > > >> >> >>> wrote:
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>> > > It was also in my spam folder... :(
> > > > > > > > > > >> >> >>> > > I've seen a bunch of apache list emails go
> to
> > > my
> > > > > spam
> > > > > > > > > > recently.
> > > > > > > > > > >> >> >>> > >
> > > > > > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell
> > > Spitzer
> > > > <
> > > > > > > > > > >> >> >>> > > russell.spitzer@gmail.com>
> > > > > > > > > > >> >> >>> > > wrote:
> > > > > > > > > > >> >> >>> > >
> > > > > > > > > > >> >> >>> > > > Yes, my hope was that my vote would kick
> it
> > > out
> > > > > of
> > > > > > > spam
> > > > > > > > > but
> > > > > > > > > > >> we
> > > > > > > > > > >> >> >>> > definitely
> > > > > > > > > > >> >> >>> > > > had two other votes that also went to
> spam
> > > for
> > > > > me.
> > > > > > > > > > >> >> >>> > > >
> > > > > > > > > > >> >> >>> > > > For anyone looking the thread is here
> > > > > > > > > > >> >> >>> > > >
> > > > > > > > > > >> >>
> > > > > > >
> https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> > > > > > > > > > >> >> >>> > > >
> > > > > > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah
> > > > Kornfield
> > > > > <
> > > > > > > > > > >> >> >>> > emkornfield@gmail.com>
> > > > > > > > > > >> >> >>> > > > wrote:
> > > > > > > > > > >> >> >>> > > >
> > > > > > > > > > >> >> >>> > > > > I've seen other's votes not go to spam,
> > so
> > > > > > > hopefully
> > > > > > > > > > people
> > > > > > > > > > >> >> will
> > > > > > > > > > >> >> >>> see
> > > > > > > > > > >> >> >>> > it
> > > > > > > > > > >> >> >>> > > > in
> > > > > > > > > > >> >> >>> > > > > there inboxes (or see this thread and
> > look
> > > in
> > > > > > there
> > > > > > > > > > spam).
> > > > > > > > > > >> >> >>> > > > >
> > > > > > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM
> PRATEEK
> > > > GAUR <
> > > > > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > > > > >> >> >>> > > > wrote:
> > > > > > > > > > >> >> >>> > > > >
> > > > > > > > > > >> >> >>> > > > > > Okay,
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > > > I sent out the voting email yesterday
> > and
> > > > so
> > > > > > far
> > > > > > > > I've
> > > > > > > > > > >> heard
> > > > > > > > > > >> >> >>> from 3
> > > > > > > > > > >> >> >>> > > > people
> > > > > > > > > > >> >> >>> > > > > > that it ended up in their "spam
> > folder".
> > > > Dev
> > > > > > VPN
> > > > > > > to
> > > > > > > > > be
> > > > > > > > > > >> >> blamed
> > > > > > > > > > >> >> >>> for
> > > > > > > > > > >> >> >>> > > it?.
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > > > What's the protocol here?
> > > > > > > > > > >> >> >>> > > > > > I let people hunt for the email in
> > their
> > > > spam
> > > > > > > > folder
> > > > > > > > > or
> > > > > > > > > > >> send
> > > > > > > > > > >> >> >>> out
> > > > > > > > > > >> >> >>> > > > another
> > > > > > > > > > >> >> >>> > > > > > one?
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > > > Best
> > > > > > > > > > >> >> >>> > > > > > Prateek
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM
> > PRATEEK
> > > > > GAUR <
> > > > > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > > > > >> >> >>> > > > > wrote:
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > > > > Hi team,
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > Vinoo has added the tests which
> were
> > > > > > requested
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > >> last
> > > > > > > > > > >> >> >>> round
> > > > > > > > > > >> >> >>> > of
> > > > > > > > > > >> >> >>> > > > > > review.
> > > > > > > > > > >> >> >>> > > > > > > In his own words.
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > "
> > > > > > > > > > >> >> >>> > > > > > > The extreme value tests Micah
> wanted
> > > are
> > > > > done
> > > > > > > and
> > > > > > > > > > >> pushed.
> > > > > > > > > > >> >> I
> > > > > > > > > > >> >> >>> added
> > > > > > > > > > >> >> >>> > > > > > coverage
> > > > > > > > > > >> >> >>> > > > > > > for values that need the full FOR
> bit
> > > > width
> > > > > > > after
> > > > > > > > > the
> > > > > > > > > > >> >> frame
> > > > > > > > > > >> >> >>> of
> > > > > > > > > > >> >> >>> > > > > reference
> > > > > > > > > > >> >> >>> > > > > > is
> > > > > > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where the
> > > > signed
> > > > > > max
> > > > > > > > > minus
> > > > > > > > > > >> min
> > > > > > > > > > >> >> >>> > > subtraction
> > > > > > > > > > >> >> >>> > > > > > > overflows), 63-bit (the
> non-overflow
> > > > case),
> > > > > > and
> > > > > > > > > > 32-bit
> > > > > > > > > > >> for
> > > > > > > > > > >> >> >>> > floats.
> > > > > > > > > > >> >> >>> > > > All
> > > > > > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I
> also
> > > > > > verified
> > > > > > > > them
> > > > > > > > > > >> >> through
> > > > > > > > > > >> >> >>> Arrow
> > > > > > > > > > >> >> >>> > > C++
> > > > > > > > > > >> >> >>> > > > > ALP
> > > > > > > > > > >> >> >>> > > > > > > reader (the local build), so the
> > > > > Java-written
> > > > > > > > > extreme
> > > > > > > > > > >> >> columns
> > > > > > > > > > >> >> >>> > > decode
> > > > > > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact against
> > the
> > > > > > > expected
> > > > > > > > > > >> values."
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > State of the PR (#3397):
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I
> > > pulled
> > > > > > > master
> > > > > > > > in
> > > > > > > > > > and
> > > > > > > > > > >> >> >>> resolved
> > > > > > > > > > >> >> >>> > > the
> > > > > > > > > > >> >> >>> > > > > > >    conflicts).
> > > > > > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads
> > resolved.
> > > > The
> > > > > 3
> > > > > > > > > > remaining
> > > > > > > > > > >> are
> > > > > > > > > > >> >> >>> > > > intentional:
> > > > > > > > > > >> >> >>> > > > > > >    one deferred perf nit, one that
> > > stays
> > > > > open
> > > > > > > > until
> > > > > > > > > > >> >> >>> > parquet-format
> > > > > > > > > > >> >> >>> > > > > ships
> > > > > > > > > > >> >> >>> > > > > > ALP,
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > "
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > With this both the
> > > > > > > > > > >> >> >>> > > > > > > 1) C++ PR :
> > > > > > > > > > >> >> >>>
> > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > > >> >> >>> > > > > > > 2) Java PR :
> > > > > > > > > > >> >> >>>
> https://github.com/apache/parquet-java/pull/3397
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > Are cross language tested and range
> > of
> > > > test
> > > > > > > > > > scenarios.
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > Best
> > > > > > > > > > >> >> >>> > > > > > > Prateek
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM
> > PRATEEK
> > > > > GAUR
> > > > > > <
> > > > > > > > > > >> >> >>> prtkgaur@gmail.com
> > > > > > > > > > >> >> >>> > >
> > > > > > > > > > >> >> >>> > > > > wrote:
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > >> Thanks Matt,
> > > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > > >> >> >>> > > > > > >> I'll be on it this week.
> > > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > > >> >> >>> > > > > > >> Best
> > > > > > > > > > >> >> >>> > > > > > >> Prateek
> > > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM
> Matt
> > > > > Topol <
> > > > > > > > > > >> >> >>> > > zotthewizard@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > > >> >> >>> > > > > > >>> There is also the Go
> implementation
> > > > > > submitted
> > > > > > > > by
> > > > > > > > > > >> Arnav (
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > https://github.com/apache/arrow-go/pull/704)
> > > > > > > > > which
> > > > > > > > > > >> is
> > > > > > > > > > >> >> >>> waiting
> > > > > > > > > > >> >> >>> > > for
> > > > > > > > > > >> >> >>> > > > > > >>> updates.
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it
> didn't
> > > get
> > > > > lost
> > > > > > > > here.
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> --Matt
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM
> > > > PRATEEK
> > > > > > > GAUR <
> > > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> > Hi all,
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > I'd like to share a status
> update
> > > on
> > > > > the
> > > > > > > ALP
> > > > > > > > > > >> encoding
> > > > > > > > > > >> >> >>> effort
> > > > > > > > > > >> >> >>> > > and
> > > > > > > > > > >> >> >>> > > > > get
> > > > > > > > > > >> >> >>> > > > > > a
> > > > > > > > > > >> >> >>> > > > > > >>> feel
> > > > > > > > > > >> >> >>> > > > > > >>> > from the community before
> > starting
> > > a
> > > > > > formal
> > > > > > > > > vote.
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > We now have the specification
> > plus
> > > > > > > > > > implementations
> > > > > > > > > > >> in
> > > > > > > > > > >> >> >>> both
> > > > > > > > > > >> >> >>> > > > > languages:
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> >     - Spec:
> > > > > > > >  apache/parquet-format#557 —
> > > > > > > > > > >> GH-533
> > > > > > > > > > >> >> >>> Add
> > > > > > > > > > >> >> >>> > ALP
> > > > > > > > > > >> >> >>> > > > > > encoding
> > > > > > > > > > >> >> >>> > > > > > >>> > specification
> > > > > > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):
> > > > apache/arrow#48345
> > > > > —
> > > > > > > > > GH-48701
> > > > > > > > > > >> >> >>> > > [C++][Parquet]
> > > > > > > > > > >> >> >>> > > > > Add
> > > > > > > > > > >> >> >>> > > > > > >>> ALPpd
> > > > > > > > > > >> >> >>> > > > > > >>> > encoding
> > > > > > > > > > >> >> >>> > > > > > >>> >     - Java:
> > > > > > >  apache/parquet-java#3397
> > > > > > > > —
> > > > > > > > > > >> Parquet
> > > > > > > > > > >> >> >>> Java
> > > > > > > > > > >> >> >>> > ALP
> > > > > > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > Current state:
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation
> has
> > > been
> > > > > > > through
> > > > > > > > > 3-4
> > > > > > > > > > >> >> rounds
> > > > > > > > > > >> >> >>> of
> > > > > > > > > > >> >> >>> > > > review.
> > > > > > > > > > >> >> >>> > > > > > >>> >     - The Java implementation
> has
> > > > been
> > > > > > > > tracking
> > > > > > > > > > >> well
> > > > > > > > > > >> >> and
> > > > > > > > > > >> >> >>> has
> > > > > > > > > > >> >> >>> > > had
> > > > > > > > > > >> >> >>> > > > > > >>> initial
> > > > > > > > > > >> >> >>> > > > > > >>> >       reviews from
> contributors,
> > > with
> > > > > no
> > > > > > > > major
> > > > > > > > > > >> >> remaining
> > > > > > > > > > >> >> >>> > > issues.
> > > > > > > > > > >> >> >>> > > > > > >>> >     - Cross-language
> > compatibility
> > > > > tests
> > > > > > > are
> > > > > > > > > > >> passing:
> > > > > > > > > > >> >> the
> > > > > > > > > > >> >> >>> > Arrow
> > > > > > > > > > >> >> >>> > > > C++
> > > > > > > > > > >> >> >>> > > > > > >>> decoder
> > > > > > > > > > >> >> >>> > > > > > >>> >       reads Java-written data
> > > > > bit-exactly
> > > > > > > > > across
> > > > > > > > > > >> >> ~1.56M
> > > > > > > > > > >> >> >>> > values
> > > > > > > > > > >> >> >>> > > > and
> > > > > > > > > > >> >> >>> > > > > 18
> > > > > > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1 and
> > V2
> > > > > pages,
> > > > > > > > > > multiple
> > > > > > > > > > >> >> vector
> > > > > > > > > > >> >> >>> > > sizes,
> > > > > > > > > > >> >> >>> > > > > and
> > > > > > > > > > >> >> >>> > > > > > >>> > several
> > > > > > > > > > >> >> >>> > > > > > >>> >       real datasets — zero
> > > > mismatches.
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we
> will
> > > be
> > > > > > adding
> > > > > > > > > > >> coverage
> > > > > > > > > > >> >> for
> > > > > > > > > > >> >> >>> > > extreme
> > > > > > > > > > >> >> >>> > > > > > values
> > > > > > > > > > >> >> >>> > > > > > >>> > (those requiring
> > > > > > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is
> applied)
> > > > > before
> > > > > > we
> > > > > > > > > > close a
> > > > > > > > > > >> >> vote.
> > > > > > > > > > >> >> >>> > We'll
> > > > > > > > > > >> >> >>> > > > aim
> > > > > > > > > > >> >> >>> > > > > > to
> > > > > > > > > > >> >> >>> > > > > > >>> get
> > > > > > > > > > >> >> >>> > > > > > >>> > that
> > > > > > > > > > >> >> >>> > > > > > >>> >  done in parallel.
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > Plan: unless there are
> > objections,
> > > I
> > > > > > intend
> > > > > > > > to
> > > > > > > > > > >> start a
> > > > > > > > > > >> >> >>> vote
> > > > > > > > > > >> >> >>> > at
> > > > > > > > > > >> >> >>> > > > the
> > > > > > > > > > >> >> >>> > > > > > end
> > > > > > > > > > >> >> >>> > > > > > >>> of
> > > > > > > > > > >> >> >>> > > > > > >>> > this week/early
> > > > > > > > > > >> >> >>> > > > > > >>> > next week.
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > Thanks
> > > > > > > > > > >> >> >>> > > > > > >>> > Prateek
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM
> > > > PRATEEK
> > > > > > > GAUR <
> > > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>> > > Hi Team,
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some
> > > updates
> > > > > on
> > > > > > > ALP.
> > > > > > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4
> > rounds
> > > of
> > > > > > > review
> > > > > > > > > for
> > > > > > > > > > >> the
> > > > > > > > > > >> >> c++
> > > > > > > > > > >> >> >>> PR :
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > https://github.com/apache/arrow/pull/48345
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > > For the Java implementation
> > Vinoo
> > > > has
> > > > > > > been
> > > > > > > > > > >> working
> > > > > > > > > > >> >> on
> > > > > > > > > > >> >> >>> > > following
> > > > > > > > > > >> >> >>> > > > > PR
> > > > > > > > > > >> >> >>> > > > > > :
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > https://github.com/apache/parquet-java/pull/3397
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > > Best
> > > > > > > > > > >> >> >>> > > > > > >>> > > Prateek
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at
> 1:50 PM
> > > > Micah
> > > > > > > > > Kornfield
> > > > > > > > > > <
> > > > > > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> > > wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question
> > was
> > > > > > already
> > > > > > > > > asked,
> > > > > > > > > > >> but
> > > > > > > > > > >> >> >>> should
> > > > > > > > > > >> >> >>> > we
> > > > > > > > > > >> >> >>> > > > > care
> > > > > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can
> FLOAT +
> > > ALP
> > > > > be
> > > > > > > more
> > > > > > > > > > >> >> efficient
> > > > > > > > > > >> >> >>> than
> > > > > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > > > > >> >> >>> > > > > > +
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4
> for
> > > > > example?
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we could
> > > defer
> > > > > it
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > >> >> >>> following
> > > > > > > > > > >> >> >>> > > > reasons:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there
> are a
> > > lot
> > > > > of
> > > > > > > easy
> > > > > > > > > > >> >> reference
> > > > > > > > > > >> >> >>> > > datasets
> > > > > > > > > > >> >> >>> > > > to
> > > > > > > > > > >> >> >>> > > > > > >>> test
> > > > > > > > > > >> >> >>> > > > > > >>> > its
> > > > > > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does look
> > > like
> > > > > > there
> > > > > > > > > might
> > > > > > > > > > be
> > > > > > > > > > >> >> one
> > > > > > > > > > >> >> >>> or
> > > > > > > > > > >> >> >>> > two
> > > > > > > > > > >> >> >>> > > on
> > > > > > > > > > >> >> >>> > > > > > >>> > huggingface
> > > > > > > > > > >> >> >>> > > > > > >>> > >> (e.g.
> > > > > > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> > > > > > > > > > >> >> >>> ).
> > > > > > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that
> > float
> > > 16
> > > > > was
> > > > > > > > more
> > > > > > > > > > >> likely
> > > > > > > > > > >> >> >>> used
> > > > > > > > > > >> >> >>> > for
> > > > > > > > > > >> >> >>> > > > > values
> > > > > > > > > > >> >> >>> > > > > > >>> that
> > > > > > > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce
> to
> > > > > decimal
> > > > > > > > > values.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an
> > > > > extension
> > > > > > > > later
> > > > > > > > > if
> > > > > > > > > > >> >> needed.
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> Cheers,
> > > > > > > > > > >> >> >>> > > > > > >>> > >> Micah
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at
> 1:40 PM
> > > > > Antoine
> > > > > > > > > Pitrou
> > > > > > > > > > <
> > > > > > > > > > >> >> >>> > > > > antoine@python.org
> > > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > > >> >> >>> > > > > > >>> > wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Hello,
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question
> > was
> > > > > > already
> > > > > > > > > asked,
> > > > > > > > > > >> but
> > > > > > > > > > >> >> >>> should
> > > > > > > > > > >> >> >>> > we
> > > > > > > > > > >> >> >>> > > > > care
> > > > > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can
> FLOAT +
> > > ALP
> > > > > be
> > > > > > > more
> > > > > > > > > > >> >> efficient
> > > > > > > > > > >> >> >>> than
> > > > > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > > > > >> >> >>> > > > > > +
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4
> for
> > > > > example?
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Regards
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10,
> > PRATEEK
> > > > > GAUR
> > > > > > a
> > > > > > > > > écrit
> > > > > > > > > > :
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah
> > for
> > > > > review
> > > > > > > > > > feedback
> > > > > > > > > > >> on
> > > > > > > > > > >> >> >>> the two
> > > > > > > > > > >> >> >>> > > > PR's
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format repo)
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> https://github.com/apache/parquet-format/pull/557
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all
> > > (unless I
> > > > > > > missed
> > > > > > > > > > >> >> something)
> > > > > > > > > > >> >> >>> > > comments
> > > > > > > > > > >> >> >>> > > > on
> > > > > > > > > > >> >> >>> > > > > > >>> the two
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > PR's.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Best
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at
> > > > 1:08 PM
> > > > > > > > PRATEEK
> > > > > > > > > > >> GAUR <
> > > > > > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and
> Micah.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of
> feedback
> > on
> > > > at
> > > > > > > least
> > > > > > > > > the
> > > > > > > > > > >> >> >>> > > implementations`
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have
> > already
> > > > > > started
> > > > > > > > > > >> addressing
> > > > > > > > > > >> >> the
> > > > > > > > > > >> >> >>> > > > > feedback, I
> > > > > > > > > > >> >> >>> > > > > > >>> > should
> > > > > > > > > > >> >> >>> > > > > > >>> > >> be
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> done with that
> > > > Monday/Tuesday.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has
> > been
> > > > > making
> > > > > > > > good
> > > > > > > > > > >> >> progress
> > > > > > > > > > >> >> >>> on
> > > > > > > > > > >> >> >>> > the
> > > > > > > > > > >> >> >>> > > > Java
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > implementation.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Best
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026 at
> > > > > 12:55 PM
> > > > > > > > Andrew
> > > > > > > > > > >> Lamb <
> > > > > > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for
> > the
> > > > > > > > > clarification
> > > > > > > > > > >> -- I
> > > > > > > > > > >> >> >>> will
> > > > > > > > > > >> >> >>> > try
> > > > > > > > > > >> >> >>> > > > and
> > > > > > > > > > >> >> >>> > > > > > look
> > > > > > > > > > >> >> >>> > > > > > >>> > into
> > > > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> > > > > > > implementation[1]
> > > > > > > > in
> > > > > > > > > > >> this
> > > > > > > > > > >> >> next
> > > > > > > > > > >> >> >>> > week
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> > > > > > > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026
> at
> > > > > 12:01 PM
> > > > > > > > Micah
> > > > > > > > > > >> >> >>> Kornfield <
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a
> fair
> > > > > amount
> > > > > > of
> > > > > > > > > > >> feedback
> > > > > > > > > > >> >> on
> > > > > > > > > > >> >> >>> at
> > > > > > > > > > >> >> >>> > > least
> > > > > > > > > > >> >> >>> > > > > the
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations,
> > > typically
> > > > I
> > > > > > > think
> > > > > > > > > > we've
> > > > > > > > > > >> >> waited
> > > > > > > > > > >> >> >>> > till
> > > > > > > > > > >> >> >>> > > > they
> > > > > > > > > > >> >> >>> > > > > > are
> > > > > > > > > > >> >> >>> > > > > > >>> > >> close to
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a
> > final
> > > > > vote.
> > > > > > > > > > >> Otherwise I
> > > > > > > > > > >> >> >>> agree
> > > > > > > > > > >> >> >>> > we
> > > > > > > > > > >> >> >>> > > > are
> > > > > > > > > > >> >> >>> > > > > > very
> > > > > > > > > > >> >> >>> > > > > > >>> > >> close.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April
> 25,
> > > > 2026,
> > > > > > > Andrew
> > > > > > > > > > Lamb
> > > > > > > > > > >> <
> > > > > > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this
> > > content
> > > > it
> > > > > > > looks
> > > > > > > > > to
> > > > > > > > > > me
> > > > > > > > > > >> >> like
> > > > > > > > > > >> >> >>> we
> > > > > > > > > > >> >> >>> > are
> > > > > > > > > > >> >> >>> > > > > ready
> > > > > > > > > > >> >> >>> > > > > > >>> to
> > > > > > > > > > >> >> >>> > > > > > >>> > >> start a
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly
> > > accept
> > > > > ALP
> > > > > > > into
> > > > > > > > > > >> Parquet
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know of
> a
> > > > reason
> > > > > > we
> > > > > > > > > should
> > > > > > > > > > >> >> >>> postpone it
> > > > > > > > > > >> >> >>> > > for
> > > > > > > > > > >> >> >>> > > > > > >>> longer?
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone
> needs
> > > some
> > > > > > more
> > > > > > > > time
> > > > > > > > > > to
> > > > > > > > > > >> >> >>> review?
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22, 2026
> > at
> > > > > > 1:00 PM
> > > > > > > > > > PRATEEK
> > > > > > > > > > >> >> GAUR <
> > > > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is
> > doing
> > > > > well.
> > > > > > I
> > > > > > > > got
> > > > > > > > > a
> > > > > > > > > > >> >> chance
> > > > > > > > > > >> >> >>> to
> > > > > > > > > > >> >> >>> > work
> > > > > > > > > > >> >> >>> > > > > > >>> through all
> > > > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback
> > and
> > > > > update
> > > > > > > the
> > > > > > > > > > spec
> > > > > > > > > > >> >> doc.
> > > > > > > > > > >> >> >>> Here
> > > > > > > > > > >> >> >>> > > are
> > > > > > > > > > >> >> >>> > > > > the
> > > > > > > > > > >> >> >>> > > > > > >>> new
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > artifacts
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > >
> > > > > > > > > > >> >> >>> > > >
> > > > > > > > > > >> >> >>> > >
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>>
> > > > > > > > > > >> >>
> > > > > > > > > > >>
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > > https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-
> > > > 3fPtD_aWt/edit
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document in
> > > > parquet
> > > > > > > > format
> > > > > > > > > > >> repo :
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> >
> > > https://github.com/apache/parquet-format/pull/557
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp
> implementation
> > > in
> > > > > > arrow
> > > > > > > > c++
> > > > > > > > > > >> repo :
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> >
> > > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp
> implementation
> > > in
> > > > > > > > > parquet-java
> > > > > > > > > > >> >> repo :
> > > > > > > > > > >> >> >>> Work
> > > > > > > > > > >> >> >>> > > for
> > > > > > > > > > >> >> >>> > > > > > >>> Vinoo and
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > Julien
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> >
> > https://github.com/apache/parquet-java/pull/3397
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test and
> > > > > > > benchmarking
> > > > > > > > > > >> >> artifacts in
> > > > > > > > > > >> >> >>> > > > > > >>> parquet-testing
> > > > > > > > > > >> >> >>> > > > > > >>> > >> repo :
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> >
> > > https://github.com/apache/parquet-testing/pull/100
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav
> just
> > > > > > submitted
> > > > > > > > an
> > > > > > > > > in
> > > > > > > > > > >> >> >>> progress
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> > > > > > > > > > >> emkornfield@gmail.com>
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> > > > > > > > > > andrewlamb11@gmail.com>
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> > 2026
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> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10,
> > 2026
> > > > at
> > > > > > > > 3:37 AM
> > > > > > > > > > >> Steve
> > > > > > > > > > >> >> >>> > Loughran <
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > stevel@cloudera.com>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb
> > 2026
> > > at
> > > > > > > 18:12,
> > > > > > > > > > Micah
> > > > > > > > > > >> >> >>> Kornfield
> > > > > > > > > > >> >> >>> > <
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > emkornfield@gmail.com>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like
> > the
> > > > > actual
> > > > > > > > issue
> > > > > > > > > > >> >> >>> described for
> > > > > > > > > > >> >> >>> > > ORC
> > > > > > > > > > >> >> >>> > > > > in
> > > > > > > > > > >> >> >>> > > > > > >>> the
> > > > > > > > > > >> >> >>> > > > > > >>> > >> paper
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
> > > > > > sub-encodings
> > > > > > > > in
> > > > > > > > > a
> > > > > > > > > > >> >> batch.
> > > > > > > > > > >> >> >>> This
> > > > > > > > > > >> >> >>> > > is
> > > > > > > > > > >> >> >>> > > > > > >>> different
> > > > > > > > > > >> >> >>> > > > > > >>> > >> then
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here
> > > where
> > > > > > there
> > > > > > > is
> > > > > > > > > > still
> > > > > > > > > > >> >> fixed
> > > > > > > > > > >> >> >>> > > > encoding
> > > > > > > > > > >> >> >>> > > > > > per
> > > > > > > > > > >> >> >>> > > > > > >>> page
> > > > > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given
> reasonably
> > > > sized
> > > > > > > > pages I
> > > > > > > > > > >> don't
> > > > > > > > > > >> >> >>> think
> > > > > > > > > > >> >> >>> > > > branch
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction
> > should
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for
> > new
> > > > > > > encodings.
> > > > > > > > > I
> > > > > > > > > > >> agree
> > > > > > > > > > >> >> >>> that
> > > > > > > > > > >> >> >>> > we
> > > > > > > > > > >> >> >>> > > > > should
> > > > > > > > > > >> >> >>> > > > > > >>> be
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for
> > adding
> > > > new
> > > > > > > > > > encodings.
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > > >> >> >>> > > > >
> > > > > > > > > > >> >> >>> > > >
> > > > > > > > > > >> >> >>> > >
> > > > > > > > > > >> >> >>> >
> > > > > > > > > > >> >> >>>
> > > > > > > > > > >> >> >>
> > > > > > > > > > >> >>
> > > > > > > > > > >> >
> > > > > > > > > > >>
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [Parquet] ALP Encoding for Floating point data

[Gunnar Morling via dev <de...@parquet.apache.org>]

Hey all,

We've added ALP encoding and decoding support to Hardwood too [1], [2].
Interop with parquet-java's implementation looks good: Hardwood decodes
pages written by parquet-java's ALP writer bit-exactly and vice versa.

Perhaps interesting: on the encoder side, we build the preset of a column
chunk from eight sample vectors distributed across the entire chunk (easy
in our case, as Hardwood's writer buffers whole chunks), whereas, IIUC,
parquet-java only samples within the first ~110K values of a chunk.
Depending on the data distribution, this can yield a more efficient
encoding, for instance when a high-cardinality column changes character
midway, e.g. moving from two to four decimal places (about 2.8× smaller in
a synthetic test with 1M doubles).

Best,

--Gunnar

[1] https://github.com/hardwood-hq/hardwood/pull/1496
[2] https://github.com/hardwood-hq/hardwood/pull/1769


On Thu, 12 Nov 2026 at 07:01, PRATEEK GAUR <pr...@gmail.com> wrote:

> Thanks everyone!
>
> On Mon, Nov 9, 2026 at 11:58 AM Vinoo Ganesh <vi...@gmail.com>
> wrote:
>
> > Thanks everyone!
> >
> > Thanks,
> > Vinoo Ganesh | vinoo.ganesh@gmail.com
> >
> > <Vi...@gmail.com>
> >
> >
> > On Mon, Nov 9, 2026 at 2:49 PM Andrew Lamb <an...@gmail.com>
> wrote:
> >
> > > The Java implementation was just merged[1]!
> > >
> > > Thank you Gang, Vinoo, Prateek and everyone who helped push that one
> > along
> > >
> > > Andrew
> > >
> > > [1]:
> https://github.com/apache/parquet-java/pull/3397#event-35545451335
> > >
> > > On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <pr...@gmail.com>
> > wrote:
> > >
> > > > Hi team,
> > > >
> > > > Quick update re: the C++ implementation.
> > > > Thanks to all the reviewers, we merged the C++ implementation today.
> > > > There are a few follow-up items that I'll address in a subsequent PR.
> > > >
> > > > Thanks
> > > > Prateek
> > > >
> > > > On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <vinoo.ganesh@gmail.com
> >
> > > > wrote:
> > > >
> > > > > Quick update re: the Java impl. Thanks for the feedback, on
> > > > > https://github.com/apache/parquet-java/pull/3397, Russel! I pulled
> > > > > https://github.com/apache/parquet-java/pull/3791 into its own PR
> > > (thanks
> > > > > for the quick approval too, Gang). Assuming no objections, I think
> we
> > > can
> > > > > merge #3791, and then go ahead of #3397.
> > > > >
> > > > > Thanks,
> > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > > >
> > > > > <Vi...@gmail.com>
> > > > >
> > > > >
> > > > > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <pr...@gmail.com>
> > > wrote:
> > > > >
> > > > > > [Rust] Awesome thanks Andrew, Kostas and Devin.
> > > > > > [Java] Thanks Gang for the feedback on Java PR.
> > > > > > [C++] Thanks Gang for another round of feedback on the C++ one.
> > > > > > [Go] Arnav and I will be working on the golang impl this week.
> > > > > >
> > > > > > This is great progress all around.
> > > > > >
> > > > > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <
> > vinoo.ganesh@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Thanks all - I'm addressing Gang's comments on
> > > > > > > https://github.com/apache/parquet-java/pull/3397 now, so
> > hopefully
> > > > > well
> > > > > > > also be in a good state for merging the java implementation
> soon.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > > > > >
> > > > > > > <Vi...@gmail.com>
> > > > > > >
> > > > > > >
> > > > > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <
> > andrewlamb11@gmail.com
> > > >
> > > > > > wrote:
> > > > > > >
> > > > > > > > We just merged the Rust implementation[1] from Kosta and
> Devan.
> > > > With
> > > > > > the
> > > > > > > > imminent release of Parquet Format 2.14.0 I think we'll be
> well
> > > on
> > > > > our
> > > > > > > way.
> > > > > > > >
> > > > > > > > Thanks again for pushing this along,
> > > > > > > > Andrew
> > > > > > > >
> > > > > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> > > > > > > >
> > > > > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <
> > prtkgaur@gmail.com>
> > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi team,
> > > > > > > > >
> > > > > > > > > Thanks Micah for multiple rounds of review and thanks Gang
> > for
> > > > > > taking a
> > > > > > > > > look at the PR and giving feedback. I've addressed all
> > comments
> > > > in
> > > > > > the
> > > > > > > > PR.
> > > > > > > > > Looking forward to the next round of feedback (or
> approval).
> > > > Would
> > > > > > like
> > > > > > > > to
> > > > > > > > > get it in soon.
> > > > > > > > >
> > > > > > > > > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > >
> > > > > > > > > With this done and after talking to Arnav, I plan to spend
> > some
> > > > > time
> > > > > > on
> > > > > > > > the
> > > > > > > > > ALP implementation in the arrow-go repository helping
> spread
> > > the
> > > > > > > support
> > > > > > > > to
> > > > > > > > > more languages.
> > > > > > > > >
> > > > > > > > > Best
> > > > > > > > > Prateek
> > > > > > > > >
> > > > > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <
> > > prtkgaur@gmail.com
> > > > >
> > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Thanks Divjot for bringing it up.
> > > > > > > > > >
> > > > > > > > > > I was under the same impression as Russell and Andrew
> that
> > > we'd
> > > > > > have
> > > > > > > it
> > > > > > > > > > flag gated.
> > > > > > > > > > With the new versioning proposal 'preview' might be a
> good
> > > tag
> > > > > for
> > > > > > > it.
> > > > > > > > > >
> > > > > > > > > > Best
> > > > > > > > > > Prateek
> > > > > > > > > >
> > > > > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> > > > > > andrewlamb11@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1]
> > (using a
> > > > > > comment
> > > > > > > > in
> > > > > > > > > >> the
> > > > > > > > > >> spec section).
> > > > > > > > > >>
> > > > > > > > > >> Russel: That is my understanding as well.
> > > > > > > > > >>
> > > > > > > > > >> Hopefully we are able to formalize the versioning
> process
> > > > > shortly
> > > > > > so
> > > > > > > > we
> > > > > > > > > >> can
> > > > > > > > > >> formalize the notion of "preview"
> > > > > > > > > >>
> > > > > > > > > >> Andrew
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> [1]: https://github.com/apache/parquet-format/pull/604
> > > > > > > > > >>
> > > > > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> > > > > > > > > >> russell.spitzer@gmail.com>
> > > > > > > > > >> wrote:
> > > > > > > > > >>
> > > > > > > > > >> > I thought we had agreed it would be merged, and
> features
> > > > like
> > > > > > this
> > > > > > > > > would
> > > > > > > > > >> > be feature flag gated. So a V-Old writer could always
> > opt
> > > in
> > > > > to
> > > > > > > > using
> > > > > > > > > >> this
> > > > > > > > > >> > encoding but that must be a conscious effort if you
> are
> > > not
> > > > > > using
> > > > > > > > > VNext
> > > > > > > > > >> of
> > > > > > > > > >> > Parquet. If you are on V-Next the writer can choose to
> > use
> > > > ALP
> > > > > > > > > whenever
> > > > > > > > > >> it
> > > > > > > > > >> > likes without user intervention.
> > > > > > > > > >> >
> > > > > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via dev <
> > > > > > > > > >> > dev@parquet.apache.org> wrote:
> > > > > > > > > >> >
> > > > > > > > > >> >> Yes, that’s my understanding as well. However, as you
> > > > noted,
> > > > > > the
> > > > > > > > > >> >> versioning
> > > > > > > > > >> >> discussion is still in early stages and hasn’t
> > prescribed
> > > > > > > concrete
> > > > > > > > > >> >> mechanisms yet. If ALP goes into parquet-format
> 2.14.0,
> > > > > there’s
> > > > > > > no
> > > > > > > > > >> >> indication that it’s in preview or that writers
> > shouldn’t
> > > > use
> > > > > > it
> > > > > > > by
> > > > > > > > > >> >> default
> > > > > > > > > >> >> yet. Given that we’ve held off on merging other
> > > > incompatible
> > > > > > > > changes
> > > > > > > > > >> (e.g
> > > > > > > > > >> >> removal of path_in_schema) until the versioning
> > > discussion
> > > > > > > closes,
> > > > > > > > my
> > > > > > > > > >> >> preference would be to leave ALP un-merged for the
> time
> > > > being
> > > > > > as
> > > > > > > > > well.
> > > > > > > > > >> >>
> > > > > > > > > >> >> — Div
> > > > > > > > > >> >>
> > > > > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> > > > > > > andrewlamb11@gmail.com>
> > > > > > > > > >> wrote:
> > > > > > > > > >> >>
> > > > > > > > > >> >> > After re-reading Julien's Versioning Proposal, my
> > > > > > understanding
> > > > > > > > is
> > > > > > > > > >> that
> > > > > > > > > >> >> if
> > > > > > > > > >> >> > we adopt that system, we will somehow mark ALP in
> > > > "Preview"
> > > > > > in
> > > > > > > > > >> >> > parquet-format for release Version 3.
> > > > > > > > > >> >> >
> > > > > > > > > >> >> > The versioning document doesn't seem to proscribe
> the
> > > > > > > particular
> > > > > > > > > >> method
> > > > > > > > > >> >> > for annotating "preview" features -- I think
> clearly
> > > > > marking
> > > > > > > them
> > > > > > > > > as
> > > > > > > > > >> >> such
> > > > > > > > > >> >> > in parquet.thrift as well as reflecting that on the
> > > > > > > > > >> >> >
> > https://parquet.apache.org/docs/file-format/versions/
> > > > page
> > > > > > > > somehow
> > > > > > > > > >> >> would
> > > > > > > > > >> >> > be adequate.
> > > > > > > > > >> >> >
> > > > > > > > > >> >> > Andrew
> > > > > > > > > >> >> >
> > > > > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> > > > > > > > > andrewlamb11@gmail.com
> > > > > > > > > >> >
> > > > > > > > > >> >> > wrote:
> > > > > > > > > >> >> >
> > > > > > > > > >> >> >> In my mind ALP is in the same position as other
> > > > encodings
> > > > > > that
> > > > > > > > > were
> > > > > > > > > >> >> added
> > > > > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non
> > > floating
> > > > > > point
> > > > > > > > > types)
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> That is to say it will be available in the latest
> > open
> > > > > > source
> > > > > > > > > >> writers
> > > > > > > > > >> >> and
> > > > > > > > > >> >> >> readers, but realistically not widely used in the
> > > > > ecosystem
> > > > > > > > where
> > > > > > > > > >> >> >> compatibility is a concern (a large part)
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> I view Julian's work[2][3] to gather consensus on
> > how
> > > to
> > > > > > name
> > > > > > > > > >> >> >> combinations of features (e.g. "versions") as the
> > > > > mechanism
> > > > > > by
> > > > > > > > > >> which we
> > > > > > > > > >> >> >> will accelerate the adoption of this change (along
> > > with
> > > > > > other
> > > > > > > > > >> forward
> > > > > > > > > >> >> >> incompatible changes) across the ecosystem.
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> > Will we exclude this change when cutting
> > > > parquet-format
> > > > > > > > v2.14.0?
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> No I don't think so -- I would expect it to go out
> > in
> > > > the
> > > > > > next
> > > > > > > > > >> >> >> parquet-format version as do other changes in the
> > > spec.
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> Andrew
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> [1]:
> > > > > https://parquet.apache.org/docs/file-format/versions/
> > > > > > > > > >> >> >> [2]:
> > > > > > > > > >>
> > > > > https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> > > > > > > > > >> >> >> [3]:
> > > > > > > > > >>
> > > > > https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora via
> > dev <
> > > > > > > > > >> >> >> dev@parquet.apache.org> wrote:
> > > > > > > > > >> >> >>
> > > > > > > > > >> >> >>> Hi Andrew,
> > > > > > > > > >> >> >>>
> > > > > > > > > >> >> >>> How does this interact with the ongoing
> versioning
> > > > > > > discussion?
> > > > > > > > > >> Given
> > > > > > > > > >> >> that
> > > > > > > > > >> >> >>> new encodings are not forward compatible, I would
> > > > assume
> > > > > > ALP
> > > > > > > is
> > > > > > > > > >> >> included
> > > > > > > > > >> >> >>> in
> > > > > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to me
> how
> > > > that
> > > > > > > works
> > > > > > > > if
> > > > > > > > > >> it's
> > > > > > > > > >> >> >>> merged to the parquet-format master branch now.
> > Will
> > > we
> > > > > > > exclude
> > > > > > > > > >> this
> > > > > > > > > >> >> >>> change
> > > > > > > > > >> >> >>> when cutting parquet-format v2.14.0?
> > > > > > > > > >> >> >>>
> > > > > > > > > >> >> >>> -- Div
> > > > > > > > > >> >> >>>
> > > > > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
> > > > > > > > > >> andrewlamb11@gmail.com>
> > > > > > > > > >> >> >>> wrote:
> > > > > > > > > >> >> >>>
> > > > > > > > > >> >> >>> > Hello,
> > > > > > > > > >> >> >>> >
> > > > > > > > > >> >> >>> > As an update, thanks to the epic work from many
> > > > > > > contributors,
> > > > > > > > > >> >> >>> especially
> > > > > > > > > >> >> >>> > Prateek, I just merged the parquet-format
> change
> > > for
> > > > > > > ALP[1].
> > > > > > > > We
> > > > > > > > > >> >> plan to
> > > > > > > > > >> >> >>> > make additional editorial The remaining items I
> > > know
> > > > of
> > > > > > are
> > > > > > > > > >> merging
> > > > > > > > > >> >> the
> > > > > > > > > >> >> >>> > examples from parquet-testing[2], and then of
> > > course
> > > > > the
> > > > > > > > > various
> > > > > > > > > >> >> >>> > implementations
> > > > > > > > > >> >> >>> >
> > > > > > > > > >> >> >>> > Thanks again everyone. This is a great step
> > forward
> > > > > > > > > >> >> >>> > Andrew
> > > > > > > > > >> >> >>> >
> > > > > > > > > >> >> >>> > [1]:
> > > > https://github.com/apache/parquet-format/pull/557
> > > > > > > > > >> >> >>> > [2]:
> > > > > https://github.com/apache/parquet-testing/pull/100
> > > > > > > > > >> >> >>> >
> > > > > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le Dem <
> > > > > > > > > julien@apache.org
> > > > > > > > > >> >
> > > > > > > > > >> >> >>> wrote:
> > > > > > > > > >> >> >>> >
> > > > > > > > > >> >> >>> > > It was also in my spam folder... :(
> > > > > > > > > >> >> >>> > > I've seen a bunch of apache list emails go to
> > my
> > > > spam
> > > > > > > > > recently.
> > > > > > > > > >> >> >>> > >
> > > > > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell
> > Spitzer
> > > <
> > > > > > > > > >> >> >>> > > russell.spitzer@gmail.com>
> > > > > > > > > >> >> >>> > > wrote:
> > > > > > > > > >> >> >>> > >
> > > > > > > > > >> >> >>> > > > Yes, my hope was that my vote would kick it
> > out
> > > > of
> > > > > > spam
> > > > > > > > but
> > > > > > > > > >> we
> > > > > > > > > >> >> >>> > definitely
> > > > > > > > > >> >> >>> > > > had two other votes that also went to spam
> > for
> > > > me.
> > > > > > > > > >> >> >>> > > >
> > > > > > > > > >> >> >>> > > > For anyone looking the thread is here
> > > > > > > > > >> >> >>> > > >
> > > > > > > > > >> >>
> > > > > > https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> > > > > > > > > >> >> >>> > > >
> > > > > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah
> > > Kornfield
> > > > <
> > > > > > > > > >> >> >>> > emkornfield@gmail.com>
> > > > > > > > > >> >> >>> > > > wrote:
> > > > > > > > > >> >> >>> > > >
> > > > > > > > > >> >> >>> > > > > I've seen other's votes not go to spam,
> so
> > > > > > hopefully
> > > > > > > > > people
> > > > > > > > > >> >> will
> > > > > > > > > >> >> >>> see
> > > > > > > > > >> >> >>> > it
> > > > > > > > > >> >> >>> > > > in
> > > > > > > > > >> >> >>> > > > > there inboxes (or see this thread and
> look
> > in
> > > > > there
> > > > > > > > > spam).
> > > > > > > > > >> >> >>> > > > >
> > > > > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM PRATEEK
> > > GAUR <
> > > > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > wrote:
> > > > > > > > > >> >> >>> > > > >
> > > > > > > > > >> >> >>> > > > > > Okay,
> > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > >> >> >>> > > > > > I sent out the voting email yesterday
> and
> > > so
> > > > > far
> > > > > > > I've
> > > > > > > > > >> heard
> > > > > > > > > >> >> >>> from 3
> > > > > > > > > >> >> >>> > > > people
> > > > > > > > > >> >> >>> > > > > > that it ended up in their "spam
> folder".
> > > Dev
> > > > > VPN
> > > > > > to
> > > > > > > > be
> > > > > > > > > >> >> blamed
> > > > > > > > > >> >> >>> for
> > > > > > > > > >> >> >>> > > it?.
> > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > >> >> >>> > > > > > What's the protocol here?
> > > > > > > > > >> >> >>> > > > > > I let people hunt for the email in
> their
> > > spam
> > > > > > > folder
> > > > > > > > or
> > > > > > > > > >> send
> > > > > > > > > >> >> >>> out
> > > > > > > > > >> >> >>> > > > another
> > > > > > > > > >> >> >>> > > > > > one?
> > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > >> >> >>> > > > > > Best
> > > > > > > > > >> >> >>> > > > > > Prateek
> > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM
> PRATEEK
> > > > GAUR <
> > > > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > > wrote:
> > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > >> >> >>> > > > > > > Hi team,
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > Vinoo has added the tests which were
> > > > > requested
> > > > > > in
> > > > > > > > the
> > > > > > > > > >> last
> > > > > > > > > >> >> >>> round
> > > > > > > > > >> >> >>> > of
> > > > > > > > > >> >> >>> > > > > > review.
> > > > > > > > > >> >> >>> > > > > > > In his own words.
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > "
> > > > > > > > > >> >> >>> > > > > > > The extreme value tests Micah wanted
> > are
> > > > done
> > > > > > and
> > > > > > > > > >> pushed.
> > > > > > > > > >> >> I
> > > > > > > > > >> >> >>> added
> > > > > > > > > >> >> >>> > > > > > coverage
> > > > > > > > > >> >> >>> > > > > > > for values that need the full FOR bit
> > > width
> > > > > > after
> > > > > > > > the
> > > > > > > > > >> >> frame
> > > > > > > > > >> >> >>> of
> > > > > > > > > >> >> >>> > > > > reference
> > > > > > > > > >> >> >>> > > > > > is
> > > > > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where the
> > > signed
> > > > > max
> > > > > > > > minus
> > > > > > > > > >> min
> > > > > > > > > >> >> >>> > > subtraction
> > > > > > > > > >> >> >>> > > > > > > overflows), 63-bit (the non-overflow
> > > case),
> > > > > and
> > > > > > > > > 32-bit
> > > > > > > > > >> for
> > > > > > > > > >> >> >>> > floats.
> > > > > > > > > >> >> >>> > > > All
> > > > > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I also
> > > > > verified
> > > > > > > them
> > > > > > > > > >> >> through
> > > > > > > > > >> >> >>> Arrow
> > > > > > > > > >> >> >>> > > C++
> > > > > > > > > >> >> >>> > > > > ALP
> > > > > > > > > >> >> >>> > > > > > > reader (the local build), so the
> > > > Java-written
> > > > > > > > extreme
> > > > > > > > > >> >> columns
> > > > > > > > > >> >> >>> > > decode
> > > > > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact against
> the
> > > > > > expected
> > > > > > > > > >> values."
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > State of the PR (#3397):
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I
> > pulled
> > > > > > master
> > > > > > > in
> > > > > > > > > and
> > > > > > > > > >> >> >>> resolved
> > > > > > > > > >> >> >>> > > the
> > > > > > > > > >> >> >>> > > > > > >    conflicts).
> > > > > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads
> resolved.
> > > The
> > > > 3
> > > > > > > > > remaining
> > > > > > > > > >> are
> > > > > > > > > >> >> >>> > > > intentional:
> > > > > > > > > >> >> >>> > > > > > >    one deferred perf nit, one that
> > stays
> > > > open
> > > > > > > until
> > > > > > > > > >> >> >>> > parquet-format
> > > > > > > > > >> >> >>> > > > > ships
> > > > > > > > > >> >> >>> > > > > > ALP,
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > "
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > With this both the
> > > > > > > > > >> >> >>> > > > > > > 1) C++ PR :
> > > > > > > > > >> >> >>>
> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > >> >> >>> > > > > > > 2) Java PR :
> > > > > > > > > >> >> >>> https://github.com/apache/parquet-java/pull/3397
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > Are cross language tested and range
> of
> > > test
> > > > > > > > > scenarios.
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > Best
> > > > > > > > > >> >> >>> > > > > > > Prateek
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM
> PRATEEK
> > > > GAUR
> > > > > <
> > > > > > > > > >> >> >>> prtkgaur@gmail.com
> > > > > > > > > >> >> >>> > >
> > > > > > > > > >> >> >>> > > > > wrote:
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > >> Thanks Matt,
> > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > >> >> >>> > > > > > >> I'll be on it this week.
> > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > >> >> >>> > > > > > >> Best
> > > > > > > > > >> >> >>> > > > > > >> Prateek
> > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM Matt
> > > > Topol <
> > > > > > > > > >> >> >>> > > zotthewizard@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >> wrote:
> > > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > > >> >> >>> > > > > > >>> There is also the Go implementation
> > > > > submitted
> > > > > > > by
> > > > > > > > > >> Arnav (
> > > > > > > > > >> >> >>> > > > > > >>>
> > > > > https://github.com/apache/arrow-go/pull/704)
> > > > > > > > which
> > > > > > > > > >> is
> > > > > > > > > >> >> >>> waiting
> > > > > > > > > >> >> >>> > > for
> > > > > > > > > >> >> >>> > > > > > >>> updates.
> > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it didn't
> > get
> > > > lost
> > > > > > > here.
> > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > >> >> >>> > > > > > >>> --Matt
> > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM
> > > PRATEEK
> > > > > > GAUR <
> > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > >> >> >>> > > > > > >>> > Hi all,
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > I'd like to share a status update
> > on
> > > > the
> > > > > > ALP
> > > > > > > > > >> encoding
> > > > > > > > > >> >> >>> effort
> > > > > > > > > >> >> >>> > > and
> > > > > > > > > >> >> >>> > > > > get
> > > > > > > > > >> >> >>> > > > > > a
> > > > > > > > > >> >> >>> > > > > > >>> feel
> > > > > > > > > >> >> >>> > > > > > >>> > from the community before
> starting
> > a
> > > > > formal
> > > > > > > > vote.
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > We now have the specification
> plus
> > > > > > > > > implementations
> > > > > > > > > >> in
> > > > > > > > > >> >> >>> both
> > > > > > > > > >> >> >>> > > > > languages:
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> >     - Spec:
> > > > > > >  apache/parquet-format#557 —
> > > > > > > > > >> GH-533
> > > > > > > > > >> >> >>> Add
> > > > > > > > > >> >> >>> > ALP
> > > > > > > > > >> >> >>> > > > > > encoding
> > > > > > > > > >> >> >>> > > > > > >>> > specification
> > > > > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):
> > > apache/arrow#48345
> > > > —
> > > > > > > > GH-48701
> > > > > > > > > >> >> >>> > > [C++][Parquet]
> > > > > > > > > >> >> >>> > > > > Add
> > > > > > > > > >> >> >>> > > > > > >>> ALPpd
> > > > > > > > > >> >> >>> > > > > > >>> > encoding
> > > > > > > > > >> >> >>> > > > > > >>> >     - Java:
> > > > > >  apache/parquet-java#3397
> > > > > > > —
> > > > > > > > > >> Parquet
> > > > > > > > > >> >> >>> Java
> > > > > > > > > >> >> >>> > ALP
> > > > > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > Current state:
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation has
> > been
> > > > > > through
> > > > > > > > 3-4
> > > > > > > > > >> >> rounds
> > > > > > > > > >> >> >>> of
> > > > > > > > > >> >> >>> > > > review.
> > > > > > > > > >> >> >>> > > > > > >>> >     - The Java implementation has
> > > been
> > > > > > > tracking
> > > > > > > > > >> well
> > > > > > > > > >> >> and
> > > > > > > > > >> >> >>> has
> > > > > > > > > >> >> >>> > > had
> > > > > > > > > >> >> >>> > > > > > >>> initial
> > > > > > > > > >> >> >>> > > > > > >>> >       reviews from contributors,
> > with
> > > > no
> > > > > > > major
> > > > > > > > > >> >> remaining
> > > > > > > > > >> >> >>> > > issues.
> > > > > > > > > >> >> >>> > > > > > >>> >     - Cross-language
> compatibility
> > > > tests
> > > > > > are
> > > > > > > > > >> passing:
> > > > > > > > > >> >> the
> > > > > > > > > >> >> >>> > Arrow
> > > > > > > > > >> >> >>> > > > C++
> > > > > > > > > >> >> >>> > > > > > >>> decoder
> > > > > > > > > >> >> >>> > > > > > >>> >       reads Java-written data
> > > > bit-exactly
> > > > > > > > across
> > > > > > > > > >> >> ~1.56M
> > > > > > > > > >> >> >>> > values
> > > > > > > > > >> >> >>> > > > and
> > > > > > > > > >> >> >>> > > > > 18
> > > > > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1 and
> V2
> > > > pages,
> > > > > > > > > multiple
> > > > > > > > > >> >> vector
> > > > > > > > > >> >> >>> > > sizes,
> > > > > > > > > >> >> >>> > > > > and
> > > > > > > > > >> >> >>> > > > > > >>> > several
> > > > > > > > > >> >> >>> > > > > > >>> >       real datasets — zero
> > > mismatches.
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we will
> > be
> > > > > adding
> > > > > > > > > >> coverage
> > > > > > > > > >> >> for
> > > > > > > > > >> >> >>> > > extreme
> > > > > > > > > >> >> >>> > > > > > values
> > > > > > > > > >> >> >>> > > > > > >>> > (those requiring
> > > > > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is applied)
> > > > before
> > > > > we
> > > > > > > > > close a
> > > > > > > > > >> >> vote.
> > > > > > > > > >> >> >>> > We'll
> > > > > > > > > >> >> >>> > > > aim
> > > > > > > > > >> >> >>> > > > > > to
> > > > > > > > > >> >> >>> > > > > > >>> get
> > > > > > > > > >> >> >>> > > > > > >>> > that
> > > > > > > > > >> >> >>> > > > > > >>> >  done in parallel.
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > Plan: unless there are
> objections,
> > I
> > > > > intend
> > > > > > > to
> > > > > > > > > >> start a
> > > > > > > > > >> >> >>> vote
> > > > > > > > > >> >> >>> > at
> > > > > > > > > >> >> >>> > > > the
> > > > > > > > > >> >> >>> > > > > > end
> > > > > > > > > >> >> >>> > > > > > >>> of
> > > > > > > > > >> >> >>> > > > > > >>> > this week/early
> > > > > > > > > >> >> >>> > > > > > >>> > next week.
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > Thanks
> > > > > > > > > >> >> >>> > > > > > >>> > Prateek
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM
> > > PRATEEK
> > > > > > GAUR <
> > > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>> > > Hi Team,
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some
> > updates
> > > > on
> > > > > > ALP.
> > > > > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4
> rounds
> > of
> > > > > > review
> > > > > > > > for
> > > > > > > > > >> the
> > > > > > > > > >> >> c++
> > > > > > > > > >> >> >>> PR :
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > https://github.com/apache/arrow/pull/48345
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > >> >> >>> > > > > > >>> > > For the Java implementation
> Vinoo
> > > has
> > > > > > been
> > > > > > > > > >> working
> > > > > > > > > >> >> on
> > > > > > > > > >> >> >>> > > following
> > > > > > > > > >> >> >>> > > > > PR
> > > > > > > > > >> >> >>> > > > > > :
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > https://github.com/apache/parquet-java/pull/3397
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > >> >> >>> > > > > > >>> > > Best
> > > > > > > > > >> >> >>> > > > > > >>> > > Prateek
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at 1:50 PM
> > > Micah
> > > > > > > > Kornfield
> > > > > > > > > <
> > > > > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > > wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question
> was
> > > > > already
> > > > > > > > asked,
> > > > > > > > > >> but
> > > > > > > > > >> >> >>> should
> > > > > > > > > >> >> >>> > we
> > > > > > > > > >> >> >>> > > > > care
> > > > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT +
> > ALP
> > > > be
> > > > > > more
> > > > > > > > > >> >> efficient
> > > > > > > > > >> >> >>> than
> > > > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > > > >> >> >>> > > > > > +
> > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> > > > example?
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we could
> > defer
> > > > it
> > > > > > for
> > > > > > > > the
> > > > > > > > > >> >> >>> following
> > > > > > > > > >> >> >>> > > > reasons:
> > > > > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there are a
> > lot
> > > > of
> > > > > > easy
> > > > > > > > > >> >> reference
> > > > > > > > > >> >> >>> > > datasets
> > > > > > > > > >> >> >>> > > > to
> > > > > > > > > >> >> >>> > > > > > >>> test
> > > > > > > > > >> >> >>> > > > > > >>> > its
> > > > > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does look
> > like
> > > > > there
> > > > > > > > might
> > > > > > > > > be
> > > > > > > > > >> >> one
> > > > > > > > > >> >> >>> or
> > > > > > > > > >> >> >>> > two
> > > > > > > > > >> >> >>> > > on
> > > > > > > > > >> >> >>> > > > > > >>> > huggingface
> > > > > > > > > >> >> >>> > > > > > >>> > >> (e.g.
> > > > > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> > > > > > > > > >> >> >>> ).
> > > > > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that
> float
> > 16
> > > > was
> > > > > > > more
> > > > > > > > > >> likely
> > > > > > > > > >> >> >>> used
> > > > > > > > > >> >> >>> > for
> > > > > > > > > >> >> >>> > > > > values
> > > > > > > > > >> >> >>> > > > > > >>> that
> > > > > > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce to
> > > > decimal
> > > > > > > > values.
> > > > > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an
> > > > extension
> > > > > > > later
> > > > > > > > if
> > > > > > > > > >> >> needed.
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> Cheers,
> > > > > > > > > >> >> >>> > > > > > >>> > >> Micah
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at 1:40 PM
> > > > Antoine
> > > > > > > > Pitrou
> > > > > > > > > <
> > > > > > > > > >> >> >>> > > > > antoine@python.org
> > > > > > > > > >> >> >>> > > > > > >
> > > > > > > > > >> >> >>> > > > > > >>> > wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Hello,
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question
> was
> > > > > already
> > > > > > > > asked,
> > > > > > > > > >> but
> > > > > > > > > >> >> >>> should
> > > > > > > > > >> >> >>> > we
> > > > > > > > > >> >> >>> > > > > care
> > > > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT +
> > ALP
> > > > be
> > > > > > more
> > > > > > > > > >> >> efficient
> > > > > > > > > >> >> >>> than
> > > > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > > > >> >> >>> > > > > > +
> > > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> > > > example?
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Regards
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10,
> PRATEEK
> > > > GAUR
> > > > > a
> > > > > > > > écrit
> > > > > > > > > :
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah
> for
> > > > review
> > > > > > > > > feedback
> > > > > > > > > >> on
> > > > > > > > > >> >> >>> the two
> > > > > > > > > >> >> >>> > > > PR's
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format repo)
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> https://github.com/apache/parquet-format/pull/557
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all
> > (unless I
> > > > > > missed
> > > > > > > > > >> >> something)
> > > > > > > > > >> >> >>> > > comments
> > > > > > > > > >> >> >>> > > > on
> > > > > > > > > >> >> >>> > > > > > >>> the two
> > > > > > > > > >> >> >>> > > > > > >>> > >> > PR's.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > Best
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at
> > > 1:08 PM
> > > > > > > PRATEEK
> > > > > > > > > >> GAUR <
> > > > > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and Micah.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of feedback
> on
> > > at
> > > > > > least
> > > > > > > > the
> > > > > > > > > >> >> >>> > > implementations`
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have
> already
> > > > > started
> > > > > > > > > >> addressing
> > > > > > > > > >> >> the
> > > > > > > > > >> >> >>> > > > > feedback, I
> > > > > > > > > >> >> >>> > > > > > >>> > should
> > > > > > > > > >> >> >>> > > > > > >>> > >> be
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> done with that
> > > Monday/Tuesday.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has
> been
> > > > making
> > > > > > > good
> > > > > > > > > >> >> progress
> > > > > > > > > >> >> >>> on
> > > > > > > > > >> >> >>> > the
> > > > > > > > > >> >> >>> > > > Java
> > > > > > > > > >> >> >>> > > > > > >>> > >> > implementation.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Best
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026 at
> > > > 12:55 PM
> > > > > > > Andrew
> > > > > > > > > >> Lamb <
> > > > > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for
> the
> > > > > > > > clarification
> > > > > > > > > >> -- I
> > > > > > > > > >> >> >>> will
> > > > > > > > > >> >> >>> > try
> > > > > > > > > >> >> >>> > > > and
> > > > > > > > > >> >> >>> > > > > > look
> > > > > > > > > >> >> >>> > > > > > >>> > into
> > > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> > > > > > implementation[1]
> > > > > > > in
> > > > > > > > > >> this
> > > > > > > > > >> >> next
> > > > > > > > > >> >> >>> > week
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> > > > > > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026 at
> > > > 12:01 PM
> > > > > > > Micah
> > > > > > > > > >> >> >>> Kornfield <
> > > > > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a fair
> > > > amount
> > > > > of
> > > > > > > > > >> feedback
> > > > > > > > > >> >> on
> > > > > > > > > >> >> >>> at
> > > > > > > > > >> >> >>> > > least
> > > > > > > > > >> >> >>> > > > > the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations,
> > typically
> > > I
> > > > > > think
> > > > > > > > > we've
> > > > > > > > > >> >> waited
> > > > > > > > > >> >> >>> > till
> > > > > > > > > >> >> >>> > > > they
> > > > > > > > > >> >> >>> > > > > > are
> > > > > > > > > >> >> >>> > > > > > >>> > >> close to
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a
> final
> > > > vote.
> > > > > > > > > >> Otherwise I
> > > > > > > > > >> >> >>> agree
> > > > > > > > > >> >> >>> > we
> > > > > > > > > >> >> >>> > > > are
> > > > > > > > > >> >> >>> > > > > > very
> > > > > > > > > >> >> >>> > > > > > >>> > >> close.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April 25,
> > > 2026,
> > > > > > Andrew
> > > > > > > > > Lamb
> > > > > > > > > >> <
> > > > > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> > > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this
> > content
> > > it
> > > > > > looks
> > > > > > > > to
> > > > > > > > > me
> > > > > > > > > >> >> like
> > > > > > > > > >> >> >>> we
> > > > > > > > > >> >> >>> > are
> > > > > > > > > >> >> >>> > > > > ready
> > > > > > > > > >> >> >>> > > > > > >>> to
> > > > > > > > > >> >> >>> > > > > > >>> > >> start a
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly
> > accept
> > > > ALP
> > > > > > into
> > > > > > > > > >> Parquet
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know of a
> > > reason
> > > > > we
> > > > > > > > should
> > > > > > > > > >> >> >>> postpone it
> > > > > > > > > >> >> >>> > > for
> > > > > > > > > >> >> >>> > > > > > >>> longer?
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone needs
> > some
> > > > > more
> > > > > > > time
> > > > > > > > > to
> > > > > > > > > >> >> >>> review?
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22, 2026
> at
> > > > > 1:00 PM
> > > > > > > > > PRATEEK
> > > > > > > > > >> >> GAUR <
> > > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is
> doing
> > > > well.
> > > > > I
> > > > > > > got
> > > > > > > > a
> > > > > > > > > >> >> chance
> > > > > > > > > >> >> >>> to
> > > > > > > > > >> >> >>> > work
> > > > > > > > > >> >> >>> > > > > > >>> through all
> > > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback
> and
> > > > update
> > > > > > the
> > > > > > > > > spec
> > > > > > > > > >> >> doc.
> > > > > > > > > >> >> >>> Here
> > > > > > > > > >> >> >>> > > are
> > > > > > > > > >> >> >>> > > > > the
> > > > > > > > > >> >> >>> > > > > > >>> new
> > > > > > > > > >> >> >>> > > > > > >>> > >> > artifacts
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > > >> >> >>> > > > > >
> > > > > > > > > >> >> >>> > > > >
> > > > > > > > > >> >> >>> > > >
> > > > > > > > > >> >> >>> > >
> > > > > > > > > >> >> >>> >
> > > > > > > > > >> >> >>>
> > > > > > > > > >> >>
> > > > > > > > > >>
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-
> > > 3fPtD_aWt/edit
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document in
> > > parquet
> > > > > > > format
> > > > > > > > > >> repo :
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> >
> > https://github.com/apache/parquet-format/pull/557
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp implementation
> > in
> > > > > arrow
> > > > > > > c++
> > > > > > > > > >> repo :
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> >
> > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp implementation
> > in
> > > > > > > > parquet-java
> > > > > > > > > >> >> repo :
> > > > > > > > > >> >> >>> Work
> > > > > > > > > >> >> >>> > > for
> > > > > > > > > >> >> >>> > > > > > >>> Vinoo and
> > > > > > > > > >> >> >>> > > > > > >>> > >> > Julien
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> >
> https://github.com/apache/parquet-java/pull/3397
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test and
> > > > > > benchmarking
> > > > > > > > > >> >> artifacts in
> > > > > > > > > >> >> >>> > > > > > >>> parquet-testing
> > > > > > > > > >> >> >>> > > > > > >>> > >> repo :
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> >
> > https://github.com/apache/parquet-testing/pull/100
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav just
> > > > > submitted
> > > > > > > an
> > > > > > > > in
> > > > > > > > > >> >> >>> progress
> > > > > > > > > >> >> >>> > > > > > >>> implementation
> > > > > > > > > >> >> >>> > > > > > >>> > in
> > > > > > > > > >> >> >>> > > > > > >>> > >> Go.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> https://github.com/apache/arrow-go/pull/704
> > > > > > > > > >> >> >>> > (I
> > > > > > > > > >> >> >>> > > > > > haven't
> > > > > > > > > >> >> >>> > > > > > >>> > >> started
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     looking at it
> yet)
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Rust : I
> remember
> > > > > Andrew
> > > > > > > > > >> mentioned
> > > > > > > > > >> >> that
> > > > > > > > > >> >> >>> > this
> > > > > > > > > >> >> >>> > > > work
> > > > > > > > > >> >> >>> > > > > > is
> > > > > > > > > >> >> >>> > > > > > >>> also
> > > > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     progress (So 4
> > > > > languages!)
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Arrow C++
> > > implementation *
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> The PR is out and was
> > > also
> > > > > used
> > > > > > > by
> > > > > > > > > >> >> Antoine to
> > > > > > > > > >> >> >>> > > report
> > > > > > > > > >> >> >>> > > > > the
> > > > > > > > > >> >> >>> > > > > > >>> > numbers
> > > > > > > > > >> >> >>> > > > > > >>> > >> as
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> reported here. Micah
> > and
> > > > > > > Konstantin
> > > > > > > > > >> have
> > > > > > > > > >> >> >>> given 1
> > > > > > > > > >> >> >>> > > > round
> > > > > > > > > >> >> >>> > > > > of
> > > > > > > > > >> >> >>> > > > > > >>> > >> feedback
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> and I'm addressing
> them
> > > > > today.
> > > > > > > > Please
> > > > > > > > > >> note
> > > > > > > > > >> >> >>> that
> > > > > > > > > >> >> >>> > the
> > > > > > > > > >> >> >>> > > > > > default
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> optimization flag for
> > > > > compiling
> > > > > > > is
> > > > > > > > O2
> > > > > > > > > >> and
> > > > > > > > > >> >> not
> > > > > > > > > >> >> >>> > Q3. I
> > > > > > > > > >> >> >>> > > > got
> > > > > > > > > >> >> >>> > > > > > >>> around
> > > > > > > > > >> >> >>> > > > > > >>> > >> 70%
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> performance
> improvement
> > > in
> > > > > the
> > > > > > > > > decoding
> > > > > > > > > >> >> speed
> > > > > > > > > >> >> >>> > when
> > > > > > > > > >> >> >>> > > > > using
> > > > > > > > > >> >> >>> > > > > > >>> the O3
> > > > > > > > > >> >> >>> > > > > > >>> > >> > flag.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Parqet-MR Java
> > > > > implementation
> > > > > > > > > (working
> > > > > > > > > >> >> with
> > > > > > > > > >> >> >>> > Vinoo
> > > > > > > > > >> >> >>> > > > and
> > > > > > > > > >> >> >>> > > > > > >>> Julien)
> > > > > > > > > >> >> >>> > > > > > >>> > >> and
> > > > > > > > > >> >> >>> > > > > > >>> > >> > **Cross
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Language testing*
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     Let me know if
> you
> > > have
> > > > > any
> > > > > > > > > >> questions
> > > > > > > > > >> >> or
> > > > > > > > > >> >> >>> > > > feedback.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
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> > > > performance
> > > > > > > > numbers
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> > > > > > > Decode —
> > > > > > > > > >> >> Spotify
> > > > > > > > > >> >> >>> > Columns
> > > > > > > > > >> >> >>> > > > > > >>> (Graviton
> > > > > > > > > >> >> >>> > > > > > >>> > 3,
> > > > > > > > > >> >> >>> > > > > > >>> > >> ARM
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Neoverse V1)
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> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
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> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> On Wed, Feb 25, 2026
> at
> > > > > 9:49 AM
> > > > > > > > > PRATEEK
> > > > > > > > > >> >> GAUR
> > > > > > > > > >> >> >>> <
> > > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com
> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Micah Kornfield <
> > > > > > > > > >> emkornfield@gmail.com>
> > > > > > > > > >> >> :
> > > > > > > > > >> >> >>> Got
> > > > > > > > > >> >> >>> > > it.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Andrew Lamb <
> > > > > > > > > andrewlamb11@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Do you think it
> would
> > > be
> > > > > good
> > > > > > > to
> > > > > > > > > >> start
> > > > > > > > > >> >> >>> moving
> > > > > > > > > >> >> >>> > the
> > > > > > > > > >> >> >>> > > > > spec
> > > > > > > > > >> >> >>> > > > > > >>> > >> development
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> into
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> markdown format, in
> > > > > > preparation
> > > > > > > > for
> > > > > > > > > >> >> >>> finalizing
> > > > > > > > > >> >> >>> > > it?
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Yes I'll update the
> > > > numbers
> > > > > > for
> > > > > > > > some
> > > > > > > > > >> of
> > > > > > > > > >> >> the
> > > > > > > > > >> >> >>> > > > examples I
> > > > > > > > > >> >> >>> > > > > > >>> have in
> > > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> spec based
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> on the updated
> header
> > > > size.
> > > > > > Then
> > > > > > > > we
> > > > > > > > > >> >> should
> > > > > > > > > >> >> >>> be
> > > > > > > > > >> >> >>> > good
> > > > > > > > > >> >> >>> > > > to
> > > > > > > > > >> >> >>> > > > > go
> > > > > > > > > >> >> >>> > > > > > >>> for
> > > > > > > > > >> >> >>> > > > > > >>> > the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> markdown format.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Thanks everyone!
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Andrew
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> On Tue, Feb 17,
> 2026
> > at
> > > > > > 7:28 PM
> > > > > > > > > >> PRATEEK
> > > > > > > > > >> >> >>> GAUR <
> > > > > > > > > >> >> >>> > > > > > >>> > >> prtkgaur@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Hi team,
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 1) Andrew
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > > working
> > > > > on
> > > > > > > test
> > > > > > > > > >> files.
> > > > > > > > > >> >> >>> My PR
> > > > > > > > > >> >> >>> > > did
> > > > > > > > > >> >> >>> > > > > add
> > > > > > > > > >> >> >>> > > > > > >>> all
> > > > > > > > > >> >> >>> > > > > > >>> > the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > test
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> files I
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     used to
> > benchmark
> > > on
> > > > > > > > datasets.
> > > > > > > > > >> >> Maybe
> > > > > > > > > >> >> >>> we
> > > > > > > > > >> >> >>> > can
> > > > > > > > > >> >> >>> > > > club
> > > > > > > > > >> >> >>> > > > > > it
> > > > > > > > > >> >> >>> > > > > > >>> > >> together.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> WIll also
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> aid
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     cross language
> > > > testing
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     -  Kosta
> Tarasov
> > > > > working
> > > > > > > on
> > > > > > > > > Rust
> > > > > > > > > >> >> >>> > > > implementation.
> > > > > > > > > >> >> >>> > > > > > >>> This is
> > > > > > > > > >> >> >>> > > > > > >>> > >> > great.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Thanks
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 2) Antoine
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks a lot
> > for
> > > > > > > reporting
> > > > > > > > > the
> > > > > > > > > >> >> >>> numbers
> > > > > > > > > >> >> >>> > on
> > > > > > > > > >> >> >>> > > > AMD.
> > > > > > > > > >> >> >>> > > > > > >>> Looks
> > > > > > > > > >> >> >>> > > > > > >>> > >> like
> > > > > > > > > >> >> >>> > > > > > >>> > >> > you
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> are
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     getting 8X the
> > > > > decoding
> > > > > > > > > >> >> performance of
> > > > > > > > > >> >> >>> > BSS.
> > > > > > > > > >> >> >>> > > > This
> > > > > > > > > >> >> >>> > > > > > is
> > > > > > > > > >> >> >>> > > > > > >>> > >> > amazing!!.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > > > > > acknowledging
> > > > > > > > the
> > > > > > > > > >> >> >>> sampling
> > > > > > > > > >> >> >>> > > > design.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - I agree with
> > you
> > > > on
> > > > > > > > > >> Fastlanes. In
> > > > > > > > > >> >> >>> some
> > > > > > > > > >> >> >>> > > crude
> > > > > > > > > >> >> >>> > > > > > >>> > >> experiments I
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> didn't get
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     a good perf
> > > benefit
> > > > > from
> > > > > > > it
> > > > > > > > on
> > > > > > > > > >> >> >>> Graviton3
> > > > > > > > > >> >> >>> > > (but
> > > > > > > > > >> >> >>> > > > > > maybe
> > > > > > > > > >> >> >>> > > > > > >>> > there
> > > > > > > > > >> >> >>> > > > > > >>> > >> was
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> something
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     wrong with my
> > > > > > > > implementation).
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Locking the
> > > 16bit
> > > > > > > > exception
> > > > > > > > > >> >> >>> encoding for
> > > > > > > > > >> >> >>> > > the
> > > > > > > > > >> >> >>> > > > > > spec
> > > > > > > > > >> >> >>> > > > > > >>> in
> > > > > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> case.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Awesome I
> > think
> > > we
> > > > > > have
> > > > > > > > > solved
> > > > > > > > > >> >> for
> > > > > > > > > >> >> >>> all
> > > > > > > > > >> >> >>> > > open
> > > > > > > > > >> >> >>> > > > > > >>> questions
> > > > > > > > > >> >> >>> > > > > > >>> > >> minus
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     version byte
> :).
> > > > (will
> > > > > > get
> > > > > > > > > back
> > > > > > > > > >> on
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> > > > > > > > > >> >> >>> > > soon)
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 3) Micah
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - FastLanes :
> > The
> > > > > > current
> > > > > > > > spec
> > > > > > > > > >> does
> > > > > > > > > >> >> >>> allow
> > > > > > > > > >> >> >>> > > for
> > > > > > > > > >> >> >>> > > > > > using
> > > > > > > > > >> >> >>> > > > > > >>> > >> FastLane
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> with the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     configurable
> > enum
> > > > > value
> > > > > > > for
> > > > > > > > > >> >> layout. We
> > > > > > > > > >> >> >>> > > should
> > > > > > > > > >> >> >>> > > > be
> > > > > > > > > >> >> >>> > > > > > >>> able to
> > > > > > > > > >> >> >>> > > > > > >>> > >> > inject
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> any
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> layout
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     in the current
> > > > design.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Working on
> resolving
> > > all
> > > > > > > > remaining
> > > > > > > > > >> open
> > > > > > > > > >> >> >>> > comments
> > > > > > > > > >> >> >>> > > > on
> > > > > > > > > >> >> >>> > > > > > the
> > > > > > > > > >> >> >>> > > > > > >>> spec
> > > > > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> week.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10,
> 2026
> > > at
> > > > > > > 3:37 AM
> > > > > > > > > >> Steve
> > > > > > > > > >> >> >>> > Loughran <
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> stevel@cloudera.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb
> 2026
> > at
> > > > > > 18:12,
> > > > > > > > > Micah
> > > > > > > > > >> >> >>> Kornfield
> > > > > > > > > >> >> >>> > <
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > emkornfield@gmail.com>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like
> the
> > > > actual
> > > > > > > issue
> > > > > > > > > >> >> >>> described for
> > > > > > > > > >> >> >>> > > ORC
> > > > > > > > > >> >> >>> > > > > in
> > > > > > > > > >> >> >>> > > > > > >>> the
> > > > > > > > > >> >> >>> > > > > > >>> > >> paper
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
> > > > > sub-encodings
> > > > > > > in
> > > > > > > > a
> > > > > > > > > >> >> batch.
> > > > > > > > > >> >> >>> This
> > > > > > > > > >> >> >>> > > is
> > > > > > > > > >> >> >>> > > > > > >>> different
> > > > > > > > > >> >> >>> > > > > > >>> > >> then
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here
> > where
> > > > > there
> > > > > > is
> > > > > > > > > still
> > > > > > > > > >> >> fixed
> > > > > > > > > >> >> >>> > > > encoding
> > > > > > > > > >> >> >>> > > > > > per
> > > > > > > > > >> >> >>> > > > > > >>> page
> > > > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given reasonably
> > > sized
> > > > > > > pages I
> > > > > > > > > >> don't
> > > > > > > > > >> >> >>> think
> > > > > > > > > >> >> >>> > > > branch
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction
> should
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for
> new
> > > > > > encodings.
> > > > > > > > I
> > > > > > > > > >> agree
> > > > > > > > > >> >> >>> that
> > > > > > > > > >> >> >>> > we
> > > > > > > > > >> >> >>> > > > > should
> > > > > > > > > >> >> >>> > > > > > >>> be
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for
> adding
> > > new
> > > > > > > > > encodings.
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> > > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
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> > > > > > > > > >> >> >>> > > > > > >>> > >> > >
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> > > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > > >> >> >>> > > > > > >>> > >>
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> > > > > > > > > >> >>
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> > > > > > > > > >>
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [Parquet] ALP Encoding for Floating point data

[PRATEEK GAUR <pr...@gmail.com>]

Thanks everyone!

On Mon, Nov 9, 2026 at 11:58 AM Vinoo Ganesh <vi...@gmail.com> wrote:

> Thanks everyone!
>
> Thanks,
> Vinoo Ganesh | vinoo.ganesh@gmail.com
>
> <Vi...@gmail.com>
>
>
> On Mon, Nov 9, 2026 at 2:49 PM Andrew Lamb <an...@gmail.com> wrote:
>
> > The Java implementation was just merged[1]!
> >
> > Thank you Gang, Vinoo, Prateek and everyone who helped push that one
> along
> >
> > Andrew
> >
> > [1]: https://github.com/apache/parquet-java/pull/3397#event-35545451335
> >
> > On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <pr...@gmail.com>
> wrote:
> >
> > > Hi team,
> > >
> > > Quick update re: the C++ implementation.
> > > Thanks to all the reviewers, we merged the C++ implementation today.
> > > There are a few follow-up items that I'll address in a subsequent PR.
> > >
> > > Thanks
> > > Prateek
> > >
> > > On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <vi...@gmail.com>
> > > wrote:
> > >
> > > > Quick update re: the Java impl. Thanks for the feedback, on
> > > > https://github.com/apache/parquet-java/pull/3397, Russel! I pulled
> > > > https://github.com/apache/parquet-java/pull/3791 into its own PR
> > (thanks
> > > > for the quick approval too, Gang). Assuming no objections, I think we
> > can
> > > > merge #3791, and then go ahead of #3397.
> > > >
> > > > Thanks,
> > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > >
> > > > <Vi...@gmail.com>
> > > >
> > > >
> > > > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <pr...@gmail.com>
> > wrote:
> > > >
> > > > > [Rust] Awesome thanks Andrew, Kostas and Devin.
> > > > > [Java] Thanks Gang for the feedback on Java PR.
> > > > > [C++] Thanks Gang for another round of feedback on the C++ one.
> > > > > [Go] Arnav and I will be working on the golang impl this week.
> > > > >
> > > > > This is great progress all around.
> > > > >
> > > > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <
> vinoo.ganesh@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Thanks all - I'm addressing Gang's comments on
> > > > > > https://github.com/apache/parquet-java/pull/3397 now, so
> hopefully
> > > > well
> > > > > > also be in a good state for merging the java implementation soon.
> > > > > >
> > > > > > Thanks,
> > > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > > > >
> > > > > > <Vi...@gmail.com>
> > > > > >
> > > > > >
> > > > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <
> andrewlamb11@gmail.com
> > >
> > > > > wrote:
> > > > > >
> > > > > > > We just merged the Rust implementation[1] from Kosta and Devan.
> > > With
> > > > > the
> > > > > > > imminent release of Parquet Format 2.14.0 I think we'll be well
> > on
> > > > our
> > > > > > way.
> > > > > > >
> > > > > > > Thanks again for pushing this along,
> > > > > > > Andrew
> > > > > > >
> > > > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> > > > > > >
> > > > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <
> prtkgaur@gmail.com>
> > > > > wrote:
> > > > > > >
> > > > > > > > Hi team,
> > > > > > > >
> > > > > > > > Thanks Micah for multiple rounds of review and thanks Gang
> for
> > > > > taking a
> > > > > > > > look at the PR and giving feedback. I've addressed all
> comments
> > > in
> > > > > the
> > > > > > > PR.
> > > > > > > > Looking forward to the next round of feedback (or approval).
> > > Would
> > > > > like
> > > > > > > to
> > > > > > > > get it in soon.
> > > > > > > >
> > > > > > > > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > >
> > > > > > > > With this done and after talking to Arnav, I plan to spend
> some
> > > > time
> > > > > on
> > > > > > > the
> > > > > > > > ALP implementation in the arrow-go repository helping spread
> > the
> > > > > > support
> > > > > > > to
> > > > > > > > more languages.
> > > > > > > >
> > > > > > > > Best
> > > > > > > > Prateek
> > > > > > > >
> > > > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <
> > prtkgaur@gmail.com
> > > >
> > > > > > wrote:
> > > > > > > >
> > > > > > > > > Thanks Divjot for bringing it up.
> > > > > > > > >
> > > > > > > > > I was under the same impression as Russell and Andrew that
> > we'd
> > > > > have
> > > > > > it
> > > > > > > > > flag gated.
> > > > > > > > > With the new versioning proposal 'preview' might be a good
> > tag
> > > > for
> > > > > > it.
> > > > > > > > >
> > > > > > > > > Best
> > > > > > > > > Prateek
> > > > > > > > >
> > > > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> > > > > andrewlamb11@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1]
> (using a
> > > > > comment
> > > > > > > in
> > > > > > > > >> the
> > > > > > > > >> spec section).
> > > > > > > > >>
> > > > > > > > >> Russel: That is my understanding as well.
> > > > > > > > >>
> > > > > > > > >> Hopefully we are able to formalize the versioning process
> > > > shortly
> > > > > so
> > > > > > > we
> > > > > > > > >> can
> > > > > > > > >> formalize the notion of "preview"
> > > > > > > > >>
> > > > > > > > >> Andrew
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> [1]: https://github.com/apache/parquet-format/pull/604
> > > > > > > > >>
> > > > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> > > > > > > > >> russell.spitzer@gmail.com>
> > > > > > > > >> wrote:
> > > > > > > > >>
> > > > > > > > >> > I thought we had agreed it would be merged, and features
> > > like
> > > > > this
> > > > > > > > would
> > > > > > > > >> > be feature flag gated. So a V-Old writer could always
> opt
> > in
> > > > to
> > > > > > > using
> > > > > > > > >> this
> > > > > > > > >> > encoding but that must be a conscious effort if you are
> > not
> > > > > using
> > > > > > > > VNext
> > > > > > > > >> of
> > > > > > > > >> > Parquet. If you are on V-Next the writer can choose to
> use
> > > ALP
> > > > > > > > whenever
> > > > > > > > >> it
> > > > > > > > >> > likes without user intervention.
> > > > > > > > >> >
> > > > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via dev <
> > > > > > > > >> > dev@parquet.apache.org> wrote:
> > > > > > > > >> >
> > > > > > > > >> >> Yes, that’s my understanding as well. However, as you
> > > noted,
> > > > > the
> > > > > > > > >> >> versioning
> > > > > > > > >> >> discussion is still in early stages and hasn’t
> prescribed
> > > > > > concrete
> > > > > > > > >> >> mechanisms yet. If ALP goes into parquet-format 2.14.0,
> > > > there’s
> > > > > > no
> > > > > > > > >> >> indication that it’s in preview or that writers
> shouldn’t
> > > use
> > > > > it
> > > > > > by
> > > > > > > > >> >> default
> > > > > > > > >> >> yet. Given that we’ve held off on merging other
> > > incompatible
> > > > > > > changes
> > > > > > > > >> (e.g
> > > > > > > > >> >> removal of path_in_schema) until the versioning
> > discussion
> > > > > > closes,
> > > > > > > my
> > > > > > > > >> >> preference would be to leave ALP un-merged for the time
> > > being
> > > > > as
> > > > > > > > well.
> > > > > > > > >> >>
> > > > > > > > >> >> — Div
> > > > > > > > >> >>
> > > > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> > > > > > andrewlamb11@gmail.com>
> > > > > > > > >> wrote:
> > > > > > > > >> >>
> > > > > > > > >> >> > After re-reading Julien's Versioning Proposal, my
> > > > > understanding
> > > > > > > is
> > > > > > > > >> that
> > > > > > > > >> >> if
> > > > > > > > >> >> > we adopt that system, we will somehow mark ALP in
> > > "Preview"
> > > > > in
> > > > > > > > >> >> > parquet-format for release Version 3.
> > > > > > > > >> >> >
> > > > > > > > >> >> > The versioning document doesn't seem to proscribe the
> > > > > > particular
> > > > > > > > >> method
> > > > > > > > >> >> > for annotating "preview" features -- I think clearly
> > > > marking
> > > > > > them
> > > > > > > > as
> > > > > > > > >> >> such
> > > > > > > > >> >> > in parquet.thrift as well as reflecting that on the
> > > > > > > > >> >> >
> https://parquet.apache.org/docs/file-format/versions/
> > > page
> > > > > > > somehow
> > > > > > > > >> >> would
> > > > > > > > >> >> > be adequate.
> > > > > > > > >> >> >
> > > > > > > > >> >> > Andrew
> > > > > > > > >> >> >
> > > > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> > > > > > > > andrewlamb11@gmail.com
> > > > > > > > >> >
> > > > > > > > >> >> > wrote:
> > > > > > > > >> >> >
> > > > > > > > >> >> >> In my mind ALP is in the same position as other
> > > encodings
> > > > > that
> > > > > > > > were
> > > > > > > > >> >> added
> > > > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non
> > floating
> > > > > point
> > > > > > > > types)
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> That is to say it will be available in the latest
> open
> > > > > source
> > > > > > > > >> writers
> > > > > > > > >> >> and
> > > > > > > > >> >> >> readers, but realistically not widely used in the
> > > > ecosystem
> > > > > > > where
> > > > > > > > >> >> >> compatibility is a concern (a large part)
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> I view Julian's work[2][3] to gather consensus on
> how
> > to
> > > > > name
> > > > > > > > >> >> >> combinations of features (e.g. "versions") as the
> > > > mechanism
> > > > > by
> > > > > > > > >> which we
> > > > > > > > >> >> >> will accelerate the adoption of this change (along
> > with
> > > > > other
> > > > > > > > >> forward
> > > > > > > > >> >> >> incompatible changes) across the ecosystem.
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> > Will we exclude this change when cutting
> > > parquet-format
> > > > > > > v2.14.0?
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> No I don't think so -- I would expect it to go out
> in
> > > the
> > > > > next
> > > > > > > > >> >> >> parquet-format version as do other changes in the
> > spec.
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> Andrew
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> [1]:
> > > > https://parquet.apache.org/docs/file-format/versions/
> > > > > > > > >> >> >> [2]:
> > > > > > > > >>
> > > > https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> > > > > > > > >> >> >> [3]:
> > > > > > > > >>
> > > > https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> > > > > > > > >> >> >>
> > > > > > > > >> >> >>
> > > > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora via
> dev <
> > > > > > > > >> >> >> dev@parquet.apache.org> wrote:
> > > > > > > > >> >> >>
> > > > > > > > >> >> >>> Hi Andrew,
> > > > > > > > >> >> >>>
> > > > > > > > >> >> >>> How does this interact with the ongoing versioning
> > > > > > discussion?
> > > > > > > > >> Given
> > > > > > > > >> >> that
> > > > > > > > >> >> >>> new encodings are not forward compatible, I would
> > > assume
> > > > > ALP
> > > > > > is
> > > > > > > > >> >> included
> > > > > > > > >> >> >>> in
> > > > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to me how
> > > that
> > > > > > works
> > > > > > > if
> > > > > > > > >> it's
> > > > > > > > >> >> >>> merged to the parquet-format master branch now.
> Will
> > we
> > > > > > exclude
> > > > > > > > >> this
> > > > > > > > >> >> >>> change
> > > > > > > > >> >> >>> when cutting parquet-format v2.14.0?
> > > > > > > > >> >> >>>
> > > > > > > > >> >> >>> -- Div
> > > > > > > > >> >> >>>
> > > > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
> > > > > > > > >> andrewlamb11@gmail.com>
> > > > > > > > >> >> >>> wrote:
> > > > > > > > >> >> >>>
> > > > > > > > >> >> >>> > Hello,
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>> > As an update, thanks to the epic work from many
> > > > > > contributors,
> > > > > > > > >> >> >>> especially
> > > > > > > > >> >> >>> > Prateek, I just merged the parquet-format change
> > for
> > > > > > ALP[1].
> > > > > > > We
> > > > > > > > >> >> plan to
> > > > > > > > >> >> >>> > make additional editorial The remaining items I
> > know
> > > of
> > > > > are
> > > > > > > > >> merging
> > > > > > > > >> >> the
> > > > > > > > >> >> >>> > examples from parquet-testing[2], and then of
> > course
> > > > the
> > > > > > > > various
> > > > > > > > >> >> >>> > implementations
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>> > Thanks again everyone. This is a great step
> forward
> > > > > > > > >> >> >>> > Andrew
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>> > [1]:
> > > https://github.com/apache/parquet-format/pull/557
> > > > > > > > >> >> >>> > [2]:
> > > > https://github.com/apache/parquet-testing/pull/100
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le Dem <
> > > > > > > > julien@apache.org
> > > > > > > > >> >
> > > > > > > > >> >> >>> wrote:
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>> > > It was also in my spam folder... :(
> > > > > > > > >> >> >>> > > I've seen a bunch of apache list emails go to
> my
> > > spam
> > > > > > > > recently.
> > > > > > > > >> >> >>> > >
> > > > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell
> Spitzer
> > <
> > > > > > > > >> >> >>> > > russell.spitzer@gmail.com>
> > > > > > > > >> >> >>> > > wrote:
> > > > > > > > >> >> >>> > >
> > > > > > > > >> >> >>> > > > Yes, my hope was that my vote would kick it
> out
> > > of
> > > > > spam
> > > > > > > but
> > > > > > > > >> we
> > > > > > > > >> >> >>> > definitely
> > > > > > > > >> >> >>> > > > had two other votes that also went to spam
> for
> > > me.
> > > > > > > > >> >> >>> > > >
> > > > > > > > >> >> >>> > > > For anyone looking the thread is here
> > > > > > > > >> >> >>> > > >
> > > > > > > > >> >>
> > > > > https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> > > > > > > > >> >> >>> > > >
> > > > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah
> > Kornfield
> > > <
> > > > > > > > >> >> >>> > emkornfield@gmail.com>
> > > > > > > > >> >> >>> > > > wrote:
> > > > > > > > >> >> >>> > > >
> > > > > > > > >> >> >>> > > > > I've seen other's votes not go to spam, so
> > > > > hopefully
> > > > > > > > people
> > > > > > > > >> >> will
> > > > > > > > >> >> >>> see
> > > > > > > > >> >> >>> > it
> > > > > > > > >> >> >>> > > > in
> > > > > > > > >> >> >>> > > > > there inboxes (or see this thread and look
> in
> > > > there
> > > > > > > > spam).
> > > > > > > > >> >> >>> > > > >
> > > > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM PRATEEK
> > GAUR <
> > > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > wrote:
> > > > > > > > >> >> >>> > > > >
> > > > > > > > >> >> >>> > > > > > Okay,
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > > > I sent out the voting email yesterday and
> > so
> > > > far
> > > > > > I've
> > > > > > > > >> heard
> > > > > > > > >> >> >>> from 3
> > > > > > > > >> >> >>> > > > people
> > > > > > > > >> >> >>> > > > > > that it ended up in their "spam folder".
> > Dev
> > > > VPN
> > > > > to
> > > > > > > be
> > > > > > > > >> >> blamed
> > > > > > > > >> >> >>> for
> > > > > > > > >> >> >>> > > it?.
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > > > What's the protocol here?
> > > > > > > > >> >> >>> > > > > > I let people hunt for the email in their
> > spam
> > > > > > folder
> > > > > > > or
> > > > > > > > >> send
> > > > > > > > >> >> >>> out
> > > > > > > > >> >> >>> > > > another
> > > > > > > > >> >> >>> > > > > > one?
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > > > Best
> > > > > > > > >> >> >>> > > > > > Prateek
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM PRATEEK
> > > GAUR <
> > > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > > wrote:
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > > > > Hi team,
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > Vinoo has added the tests which were
> > > > requested
> > > > > in
> > > > > > > the
> > > > > > > > >> last
> > > > > > > > >> >> >>> round
> > > > > > > > >> >> >>> > of
> > > > > > > > >> >> >>> > > > > > review.
> > > > > > > > >> >> >>> > > > > > > In his own words.
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > "
> > > > > > > > >> >> >>> > > > > > > The extreme value tests Micah wanted
> are
> > > done
> > > > > and
> > > > > > > > >> pushed.
> > > > > > > > >> >> I
> > > > > > > > >> >> >>> added
> > > > > > > > >> >> >>> > > > > > coverage
> > > > > > > > >> >> >>> > > > > > > for values that need the full FOR bit
> > width
> > > > > after
> > > > > > > the
> > > > > > > > >> >> frame
> > > > > > > > >> >> >>> of
> > > > > > > > >> >> >>> > > > > reference
> > > > > > > > >> >> >>> > > > > > is
> > > > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where the
> > signed
> > > > max
> > > > > > > minus
> > > > > > > > >> min
> > > > > > > > >> >> >>> > > subtraction
> > > > > > > > >> >> >>> > > > > > > overflows), 63-bit (the non-overflow
> > case),
> > > > and
> > > > > > > > 32-bit
> > > > > > > > >> for
> > > > > > > > >> >> >>> > floats.
> > > > > > > > >> >> >>> > > > All
> > > > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I also
> > > > verified
> > > > > > them
> > > > > > > > >> >> through
> > > > > > > > >> >> >>> Arrow
> > > > > > > > >> >> >>> > > C++
> > > > > > > > >> >> >>> > > > > ALP
> > > > > > > > >> >> >>> > > > > > > reader (the local build), so the
> > > Java-written
> > > > > > > extreme
> > > > > > > > >> >> columns
> > > > > > > > >> >> >>> > > decode
> > > > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact against the
> > > > > expected
> > > > > > > > >> values."
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > State of the PR (#3397):
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I
> pulled
> > > > > master
> > > > > > in
> > > > > > > > and
> > > > > > > > >> >> >>> resolved
> > > > > > > > >> >> >>> > > the
> > > > > > > > >> >> >>> > > > > > >    conflicts).
> > > > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads resolved.
> > The
> > > 3
> > > > > > > > remaining
> > > > > > > > >> are
> > > > > > > > >> >> >>> > > > intentional:
> > > > > > > > >> >> >>> > > > > > >    one deferred perf nit, one that
> stays
> > > open
> > > > > > until
> > > > > > > > >> >> >>> > parquet-format
> > > > > > > > >> >> >>> > > > > ships
> > > > > > > > >> >> >>> > > > > > ALP,
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > "
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > With this both the
> > > > > > > > >> >> >>> > > > > > > 1) C++ PR :
> > > > > > > > >> >> >>> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > >> >> >>> > > > > > > 2) Java PR :
> > > > > > > > >> >> >>> https://github.com/apache/parquet-java/pull/3397
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > Are cross language tested and range of
> > test
> > > > > > > > scenarios.
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > Best
> > > > > > > > >> >> >>> > > > > > > Prateek
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM PRATEEK
> > > GAUR
> > > > <
> > > > > > > > >> >> >>> prtkgaur@gmail.com
> > > > > > > > >> >> >>> > >
> > > > > > > > >> >> >>> > > > > wrote:
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > >> Thanks Matt,
> > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > >> >> >>> > > > > > >> I'll be on it this week.
> > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > >> >> >>> > > > > > >> Best
> > > > > > > > >> >> >>> > > > > > >> Prateek
> > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM Matt
> > > Topol <
> > > > > > > > >> >> >>> > > zotthewizard@gmail.com>
> > > > > > > > >> >> >>> > > > > > >> wrote:
> > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > >> >> >>> > > > > > >>> There is also the Go implementation
> > > > submitted
> > > > > > by
> > > > > > > > >> Arnav (
> > > > > > > > >> >> >>> > > > > > >>>
> > > > https://github.com/apache/arrow-go/pull/704)
> > > > > > > which
> > > > > > > > >> is
> > > > > > > > >> >> >>> waiting
> > > > > > > > >> >> >>> > > for
> > > > > > > > >> >> >>> > > > > > >>> updates.
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it didn't
> get
> > > lost
> > > > > > here.
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>> > > > > > >>> --Matt
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM
> > PRATEEK
> > > > > GAUR <
> > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>> > > > > > >>> > Hi all,
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > I'd like to share a status update
> on
> > > the
> > > > > ALP
> > > > > > > > >> encoding
> > > > > > > > >> >> >>> effort
> > > > > > > > >> >> >>> > > and
> > > > > > > > >> >> >>> > > > > get
> > > > > > > > >> >> >>> > > > > > a
> > > > > > > > >> >> >>> > > > > > >>> feel
> > > > > > > > >> >> >>> > > > > > >>> > from the community before starting
> a
> > > > formal
> > > > > > > vote.
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > We now have the specification plus
> > > > > > > > implementations
> > > > > > > > >> in
> > > > > > > > >> >> >>> both
> > > > > > > > >> >> >>> > > > > languages:
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> >     - Spec:
> > > > > >  apache/parquet-format#557 —
> > > > > > > > >> GH-533
> > > > > > > > >> >> >>> Add
> > > > > > > > >> >> >>> > ALP
> > > > > > > > >> >> >>> > > > > > encoding
> > > > > > > > >> >> >>> > > > > > >>> > specification
> > > > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):
> > apache/arrow#48345
> > > —
> > > > > > > GH-48701
> > > > > > > > >> >> >>> > > [C++][Parquet]
> > > > > > > > >> >> >>> > > > > Add
> > > > > > > > >> >> >>> > > > > > >>> ALPpd
> > > > > > > > >> >> >>> > > > > > >>> > encoding
> > > > > > > > >> >> >>> > > > > > >>> >     - Java:
> > > > >  apache/parquet-java#3397
> > > > > > —
> > > > > > > > >> Parquet
> > > > > > > > >> >> >>> Java
> > > > > > > > >> >> >>> > ALP
> > > > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > Current state:
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation has
> been
> > > > > through
> > > > > > > 3-4
> > > > > > > > >> >> rounds
> > > > > > > > >> >> >>> of
> > > > > > > > >> >> >>> > > > review.
> > > > > > > > >> >> >>> > > > > > >>> >     - The Java implementation has
> > been
> > > > > > tracking
> > > > > > > > >> well
> > > > > > > > >> >> and
> > > > > > > > >> >> >>> has
> > > > > > > > >> >> >>> > > had
> > > > > > > > >> >> >>> > > > > > >>> initial
> > > > > > > > >> >> >>> > > > > > >>> >       reviews from contributors,
> with
> > > no
> > > > > > major
> > > > > > > > >> >> remaining
> > > > > > > > >> >> >>> > > issues.
> > > > > > > > >> >> >>> > > > > > >>> >     - Cross-language compatibility
> > > tests
> > > > > are
> > > > > > > > >> passing:
> > > > > > > > >> >> the
> > > > > > > > >> >> >>> > Arrow
> > > > > > > > >> >> >>> > > > C++
> > > > > > > > >> >> >>> > > > > > >>> decoder
> > > > > > > > >> >> >>> > > > > > >>> >       reads Java-written data
> > > bit-exactly
> > > > > > > across
> > > > > > > > >> >> ~1.56M
> > > > > > > > >> >> >>> > values
> > > > > > > > >> >> >>> > > > and
> > > > > > > > >> >> >>> > > > > 18
> > > > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1 and V2
> > > pages,
> > > > > > > > multiple
> > > > > > > > >> >> vector
> > > > > > > > >> >> >>> > > sizes,
> > > > > > > > >> >> >>> > > > > and
> > > > > > > > >> >> >>> > > > > > >>> > several
> > > > > > > > >> >> >>> > > > > > >>> >       real datasets — zero
> > mismatches.
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we will
> be
> > > > adding
> > > > > > > > >> coverage
> > > > > > > > >> >> for
> > > > > > > > >> >> >>> > > extreme
> > > > > > > > >> >> >>> > > > > > values
> > > > > > > > >> >> >>> > > > > > >>> > (those requiring
> > > > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is applied)
> > > before
> > > > we
> > > > > > > > close a
> > > > > > > > >> >> vote.
> > > > > > > > >> >> >>> > We'll
> > > > > > > > >> >> >>> > > > aim
> > > > > > > > >> >> >>> > > > > > to
> > > > > > > > >> >> >>> > > > > > >>> get
> > > > > > > > >> >> >>> > > > > > >>> > that
> > > > > > > > >> >> >>> > > > > > >>> >  done in parallel.
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > Plan: unless there are objections,
> I
> > > > intend
> > > > > > to
> > > > > > > > >> start a
> > > > > > > > >> >> >>> vote
> > > > > > > > >> >> >>> > at
> > > > > > > > >> >> >>> > > > the
> > > > > > > > >> >> >>> > > > > > end
> > > > > > > > >> >> >>> > > > > > >>> of
> > > > > > > > >> >> >>> > > > > > >>> > this week/early
> > > > > > > > >> >> >>> > > > > > >>> > next week.
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > Thanks
> > > > > > > > >> >> >>> > > > > > >>> > Prateek
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM
> > PRATEEK
> > > > > GAUR <
> > > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>> > > Hi Team,
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some
> updates
> > > on
> > > > > ALP.
> > > > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4 rounds
> of
> > > > > review
> > > > > > > for
> > > > > > > > >> the
> > > > > > > > >> >> c++
> > > > > > > > >> >> >>> PR :
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > https://github.com/apache/arrow/pull/48345
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> > > For the Java implementation Vinoo
> > has
> > > > > been
> > > > > > > > >> working
> > > > > > > > >> >> on
> > > > > > > > >> >> >>> > > following
> > > > > > > > >> >> >>> > > > > PR
> > > > > > > > >> >> >>> > > > > > :
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > https://github.com/apache/parquet-java/pull/3397
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> > > Best
> > > > > > > > >> >> >>> > > > > > >>> > > Prateek
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at 1:50 PM
> > Micah
> > > > > > > Kornfield
> > > > > > > > <
> > > > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > > wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> > > > already
> > > > > > > asked,
> > > > > > > > >> but
> > > > > > > > >> >> >>> should
> > > > > > > > >> >> >>> > we
> > > > > > > > >> >> >>> > > > > care
> > > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT +
> ALP
> > > be
> > > > > more
> > > > > > > > >> >> efficient
> > > > > > > > >> >> >>> than
> > > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > > >> >> >>> > > > > > +
> > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> > > example?
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we could
> defer
> > > it
> > > > > for
> > > > > > > the
> > > > > > > > >> >> >>> following
> > > > > > > > >> >> >>> > > > reasons:
> > > > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there are a
> lot
> > > of
> > > > > easy
> > > > > > > > >> >> reference
> > > > > > > > >> >> >>> > > datasets
> > > > > > > > >> >> >>> > > > to
> > > > > > > > >> >> >>> > > > > > >>> test
> > > > > > > > >> >> >>> > > > > > >>> > its
> > > > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does look
> like
> > > > there
> > > > > > > might
> > > > > > > > be
> > > > > > > > >> >> one
> > > > > > > > >> >> >>> or
> > > > > > > > >> >> >>> > two
> > > > > > > > >> >> >>> > > on
> > > > > > > > >> >> >>> > > > > > >>> > huggingface
> > > > > > > > >> >> >>> > > > > > >>> > >> (e.g.
> > > > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> > > > > > > > >> >> >>> ).
> > > > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that float
> 16
> > > was
> > > > > > more
> > > > > > > > >> likely
> > > > > > > > >> >> >>> used
> > > > > > > > >> >> >>> > for
> > > > > > > > >> >> >>> > > > > values
> > > > > > > > >> >> >>> > > > > > >>> that
> > > > > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce to
> > > decimal
> > > > > > > values.
> > > > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an
> > > extension
> > > > > > later
> > > > > > > if
> > > > > > > > >> >> needed.
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> Cheers,
> > > > > > > > >> >> >>> > > > > > >>> > >> Micah
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at 1:40 PM
> > > Antoine
> > > > > > > Pitrou
> > > > > > > > <
> > > > > > > > >> >> >>> > > > > antoine@python.org
> > > > > > > > >> >> >>> > > > > > >
> > > > > > > > >> >> >>> > > > > > >>> > wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > Hello,
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> > > > already
> > > > > > > asked,
> > > > > > > > >> but
> > > > > > > > >> >> >>> should
> > > > > > > > >> >> >>> > we
> > > > > > > > >> >> >>> > > > > care
> > > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT +
> ALP
> > > be
> > > > > more
> > > > > > > > >> >> efficient
> > > > > > > > >> >> >>> than
> > > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > > >> >> >>> > > > > > +
> > > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> > > example?
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > Regards
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10, PRATEEK
> > > GAUR
> > > > a
> > > > > > > écrit
> > > > > > > > :
> > > > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah for
> > > review
> > > > > > > > feedback
> > > > > > > > >> on
> > > > > > > > >> >> >>> the two
> > > > > > > > >> >> >>> > > > PR's
> > > > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format repo)
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> https://github.com/apache/parquet-format/pull/557
> > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all
> (unless I
> > > > > missed
> > > > > > > > >> >> something)
> > > > > > > > >> >> >>> > > comments
> > > > > > > > >> >> >>> > > > on
> > > > > > > > >> >> >>> > > > > > >>> the two
> > > > > > > > >> >> >>> > > > > > >>> > >> > PR's.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> > > Best
> > > > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at
> > 1:08 PM
> > > > > > PRATEEK
> > > > > > > > >> GAUR <
> > > > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and Micah.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of feedback on
> > at
> > > > > least
> > > > > > > the
> > > > > > > > >> >> >>> > > implementations`
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have already
> > > > started
> > > > > > > > >> addressing
> > > > > > > > >> >> the
> > > > > > > > >> >> >>> > > > > feedback, I
> > > > > > > > >> >> >>> > > > > > >>> > should
> > > > > > > > >> >> >>> > > > > > >>> > >> be
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> done with that
> > Monday/Tuesday.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has been
> > > making
> > > > > > good
> > > > > > > > >> >> progress
> > > > > > > > >> >> >>> on
> > > > > > > > >> >> >>> > the
> > > > > > > > >> >> >>> > > > Java
> > > > > > > > >> >> >>> > > > > > >>> > >> > implementation.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> Best
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026 at
> > > 12:55 PM
> > > > > > Andrew
> > > > > > > > >> Lamb <
> > > > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for the
> > > > > > > clarification
> > > > > > > > >> -- I
> > > > > > > > >> >> >>> will
> > > > > > > > >> >> >>> > try
> > > > > > > > >> >> >>> > > > and
> > > > > > > > >> >> >>> > > > > > look
> > > > > > > > >> >> >>> > > > > > >>> > into
> > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> > > > > implementation[1]
> > > > > > in
> > > > > > > > >> this
> > > > > > > > >> >> next
> > > > > > > > >> >> >>> > week
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> > > > > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026 at
> > > 12:01 PM
> > > > > > Micah
> > > > > > > > >> >> >>> Kornfield <
> > > > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a fair
> > > amount
> > > > of
> > > > > > > > >> feedback
> > > > > > > > >> >> on
> > > > > > > > >> >> >>> at
> > > > > > > > >> >> >>> > > least
> > > > > > > > >> >> >>> > > > > the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations,
> typically
> > I
> > > > > think
> > > > > > > > we've
> > > > > > > > >> >> waited
> > > > > > > > >> >> >>> > till
> > > > > > > > >> >> >>> > > > they
> > > > > > > > >> >> >>> > > > > > are
> > > > > > > > >> >> >>> > > > > > >>> > >> close to
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a final
> > > vote.
> > > > > > > > >> Otherwise I
> > > > > > > > >> >> >>> agree
> > > > > > > > >> >> >>> > we
> > > > > > > > >> >> >>> > > > are
> > > > > > > > >> >> >>> > > > > > very
> > > > > > > > >> >> >>> > > > > > >>> > >> close.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April 25,
> > 2026,
> > > > > Andrew
> > > > > > > > Lamb
> > > > > > > > >> <
> > > > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> > wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this
> content
> > it
> > > > > looks
> > > > > > > to
> > > > > > > > me
> > > > > > > > >> >> like
> > > > > > > > >> >> >>> we
> > > > > > > > >> >> >>> > are
> > > > > > > > >> >> >>> > > > > ready
> > > > > > > > >> >> >>> > > > > > >>> to
> > > > > > > > >> >> >>> > > > > > >>> > >> start a
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly
> accept
> > > ALP
> > > > > into
> > > > > > > > >> Parquet
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know of a
> > reason
> > > > we
> > > > > > > should
> > > > > > > > >> >> >>> postpone it
> > > > > > > > >> >> >>> > > for
> > > > > > > > >> >> >>> > > > > > >>> longer?
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone needs
> some
> > > > more
> > > > > > time
> > > > > > > > to
> > > > > > > > >> >> >>> review?
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22, 2026 at
> > > > 1:00 PM
> > > > > > > > PRATEEK
> > > > > > > > >> >> GAUR <
> > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is doing
> > > well.
> > > > I
> > > > > > got
> > > > > > > a
> > > > > > > > >> >> chance
> > > > > > > > >> >> >>> to
> > > > > > > > >> >> >>> > work
> > > > > > > > >> >> >>> > > > > > >>> through all
> > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback and
> > > update
> > > > > the
> > > > > > > > spec
> > > > > > > > >> >> doc.
> > > > > > > > >> >> >>> Here
> > > > > > > > >> >> >>> > > are
> > > > > > > > >> >> >>> > > > > the
> > > > > > > > >> >> >>> > > > > > >>> new
> > > > > > > > >> >> >>> > > > > > >>> > >> > artifacts
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > >
> > > > > > > > >> >> >>> > > >
> > > > > > > > >> >> >>> > >
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>>
> > > > > > > > >> >>
> > > > > > > > >>
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > > https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-
> > 3fPtD_aWt/edit
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document in
> > parquet
> > > > > > format
> > > > > > > > >> repo :
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> >
> https://github.com/apache/parquet-format/pull/557
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp implementation
> in
> > > > arrow
> > > > > > c++
> > > > > > > > >> repo :
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> >
> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp implementation
> in
> > > > > > > parquet-java
> > > > > > > > >> >> repo :
> > > > > > > > >> >> >>> Work
> > > > > > > > >> >> >>> > > for
> > > > > > > > >> >> >>> > > > > > >>> Vinoo and
> > > > > > > > >> >> >>> > > > > > >>> > >> > Julien
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > https://github.com/apache/parquet-java/pull/3397
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test and
> > > > > benchmarking
> > > > > > > > >> >> artifacts in
> > > > > > > > >> >> >>> > > > > > >>> parquet-testing
> > > > > > > > >> >> >>> > > > > > >>> > >> repo :
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> >
> https://github.com/apache/parquet-testing/pull/100
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav just
> > > > submitted
> > > > > > an
> > > > > > > in
> > > > > > > > >> >> >>> progress
> > > > > > > > >> >> >>> > > > > > >>> implementation
> > > > > > > > >> >> >>> > > > > > >>> > in
> > > > > > > > >> >> >>> > > > > > >>> > >> Go.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> https://github.com/apache/arrow-go/pull/704
> > > > > > > > >> >> >>> > (I
> > > > > > > > >> >> >>> > > > > > haven't
> > > > > > > > >> >> >>> > > > > > >>> > >> started
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     looking at it yet)
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Rust : I remember
> > > > Andrew
> > > > > > > > >> mentioned
> > > > > > > > >> >> that
> > > > > > > > >> >> >>> > this
> > > > > > > > >> >> >>> > > > work
> > > > > > > > >> >> >>> > > > > > is
> > > > > > > > >> >> >>> > > > > > >>> also
> > > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     progress (So 4
> > > > languages!)
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Arrow C++
> > implementation *
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> The PR is out and was
> > also
> > > > used
> > > > > > by
> > > > > > > > >> >> Antoine to
> > > > > > > > >> >> >>> > > report
> > > > > > > > >> >> >>> > > > > the
> > > > > > > > >> >> >>> > > > > > >>> > numbers
> > > > > > > > >> >> >>> > > > > > >>> > >> as
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> reported here. Micah
> and
> > > > > > Konstantin
> > > > > > > > >> have
> > > > > > > > >> >> >>> given 1
> > > > > > > > >> >> >>> > > > round
> > > > > > > > >> >> >>> > > > > of
> > > > > > > > >> >> >>> > > > > > >>> > >> feedback
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> and I'm addressing them
> > > > today.
> > > > > > > Please
> > > > > > > > >> note
> > > > > > > > >> >> >>> that
> > > > > > > > >> >> >>> > the
> > > > > > > > >> >> >>> > > > > > default
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> optimization flag for
> > > > compiling
> > > > > > is
> > > > > > > O2
> > > > > > > > >> and
> > > > > > > > >> >> not
> > > > > > > > >> >> >>> > Q3. I
> > > > > > > > >> >> >>> > > > got
> > > > > > > > >> >> >>> > > > > > >>> around
> > > > > > > > >> >> >>> > > > > > >>> > >> 70%
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> performance improvement
> > in
> > > > the
> > > > > > > > decoding
> > > > > > > > >> >> speed
> > > > > > > > >> >> >>> > when
> > > > > > > > >> >> >>> > > > > using
> > > > > > > > >> >> >>> > > > > > >>> the O3
> > > > > > > > >> >> >>> > > > > > >>> > >> > flag.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Parqet-MR Java
> > > > implementation
> > > > > > > > (working
> > > > > > > > >> >> with
> > > > > > > > >> >> >>> > Vinoo
> > > > > > > > >> >> >>> > > > and
> > > > > > > > >> >> >>> > > > > > >>> Julien)
> > > > > > > > >> >> >>> > > > > > >>> > >> and
> > > > > > > > >> >> >>> > > > > > >>> > >> > **Cross
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Language testing*
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     Let me know if you
> > have
> > > > any
> > > > > > > > >> questions
> > > > > > > > >> >> or
> > > > > > > > >> >> >>> > > > feedback.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Now pasting some
> > > performance
> > > > > > > numbers
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    Table 1: C++ ALP
> > Double
> > > > > > Decode —
> > > > > > > > >> >> Spotify
> > > > > > > > >> >> >>> > Columns
> > > > > > > > >> >> >>> > > > > > >>> (Graviton
> > > > > > > > >> >> >>> > > > > > >>> > 3,
> > > > > > > > >> >> >>> > > > > > >>> > >> ARM
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Neoverse V1)
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>>
> > > > > ┌──────────────────┬──────────────┬──────────────┬─────────┐
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ Column           │
> > > -O2
> > > > > > (MB/s)
> > > > > > > > │
> > > > > > > > >> >> -O3
> > > > > > > > >> >> >>> > > (MB/s)  │
> > > > > > > > >> >> >>> > > > > > >>> Speedup │
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>>
> > > > > ├──────────────────┼──────────────┼──────────────┼─────────┤
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ valence          │
> > > > >  3,155
> > > > > > > > │
> > > > > > > > >> >> >>>  5,523
> > > > > > > > >> >> >>> > >   │
> > > > > > > > >> >> >>> > > > > > >>> 1.75x  │
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ danceability     │
> > > > >  3,233
> > > > > > > > │
> > > > > > > > >> >> >>>  5,685
> > > > > > > > >> >> >>> > >   │
> > > > > > > > >> >> >>> > > > > > >>> 1.76x  │
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ energy           │
> > > > >  3,197
> > > > > > > > │
> > > > > > > > >> >> >>>  5,652
> > > > > > > > >> >> >>> > >   │
> > > > > > > > >> >> >>> > > > > > >>> 1.77x  │
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ loudness         │
> > > > >  3,186
> > > > > > > > │
> > > > > > > > >> >> >>>  5,473
> > > > > > > > >> >> >>> > >   │
> > > > > > > > >> >> >>> > > > > > >>> 1.72x  │
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>>
> > > > > └──────────────────┴──────────────┴──────────────┴─────────┘
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> On Wed, Feb 25, 2026 at
> > > > 9:49 AM
> > > > > > > > PRATEEK
> > > > > > > > >> >> GAUR
> > > > > > > > >> >> >>> <
> > > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Micah Kornfield <
> > > > > > > > >> emkornfield@gmail.com>
> > > > > > > > >> >> :
> > > > > > > > >> >> >>> Got
> > > > > > > > >> >> >>> > > it.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Andrew Lamb <
> > > > > > > > andrewlamb11@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Do you think it would
> > be
> > > > good
> > > > > > to
> > > > > > > > >> start
> > > > > > > > >> >> >>> moving
> > > > > > > > >> >> >>> > the
> > > > > > > > >> >> >>> > > > > spec
> > > > > > > > >> >> >>> > > > > > >>> > >> development
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> into
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> markdown format, in
> > > > > preparation
> > > > > > > for
> > > > > > > > >> >> >>> finalizing
> > > > > > > > >> >> >>> > > it?
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Yes I'll update the
> > > numbers
> > > > > for
> > > > > > > some
> > > > > > > > >> of
> > > > > > > > >> >> the
> > > > > > > > >> >> >>> > > > examples I
> > > > > > > > >> >> >>> > > > > > >>> have in
> > > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> spec based
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> on the updated header
> > > size.
> > > > > Then
> > > > > > > we
> > > > > > > > >> >> should
> > > > > > > > >> >> >>> be
> > > > > > > > >> >> >>> > good
> > > > > > > > >> >> >>> > > > to
> > > > > > > > >> >> >>> > > > > go
> > > > > > > > >> >> >>> > > > > > >>> for
> > > > > > > > >> >> >>> > > > > > >>> > the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> markdown format.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Thanks everyone!
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Andrew
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> On Tue, Feb 17, 2026
> at
> > > > > 7:28 PM
> > > > > > > > >> PRATEEK
> > > > > > > > >> >> >>> GAUR <
> > > > > > > > >> >> >>> > > > > > >>> > >> prtkgaur@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Hi team,
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 1) Andrew
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > working
> > > > on
> > > > > > test
> > > > > > > > >> files.
> > > > > > > > >> >> >>> My PR
> > > > > > > > >> >> >>> > > did
> > > > > > > > >> >> >>> > > > > add
> > > > > > > > >> >> >>> > > > > > >>> all
> > > > > > > > >> >> >>> > > > > > >>> > the
> > > > > > > > >> >> >>> > > > > > >>> > >> > test
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> files I
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     used to
> benchmark
> > on
> > > > > > > datasets.
> > > > > > > > >> >> Maybe
> > > > > > > > >> >> >>> we
> > > > > > > > >> >> >>> > can
> > > > > > > > >> >> >>> > > > club
> > > > > > > > >> >> >>> > > > > > it
> > > > > > > > >> >> >>> > > > > > >>> > >> together.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> WIll also
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> aid
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     cross language
> > > testing
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     -  Kosta Tarasov
> > > > working
> > > > > > on
> > > > > > > > Rust
> > > > > > > > >> >> >>> > > > implementation.
> > > > > > > > >> >> >>> > > > > > >>> This is
> > > > > > > > >> >> >>> > > > > > >>> > >> > great.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Thanks
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 2) Antoine
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks a lot
> for
> > > > > > reporting
> > > > > > > > the
> > > > > > > > >> >> >>> numbers
> > > > > > > > >> >> >>> > on
> > > > > > > > >> >> >>> > > > AMD.
> > > > > > > > >> >> >>> > > > > > >>> Looks
> > > > > > > > >> >> >>> > > > > > >>> > >> like
> > > > > > > > >> >> >>> > > > > > >>> > >> > you
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> are
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     getting 8X the
> > > > decoding
> > > > > > > > >> >> performance of
> > > > > > > > >> >> >>> > BSS.
> > > > > > > > >> >> >>> > > > This
> > > > > > > > >> >> >>> > > > > > is
> > > > > > > > >> >> >>> > > > > > >>> > >> > amazing!!.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > > > > acknowledging
> > > > > > > the
> > > > > > > > >> >> >>> sampling
> > > > > > > > >> >> >>> > > > design.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - I agree with
> you
> > > on
> > > > > > > > >> Fastlanes. In
> > > > > > > > >> >> >>> some
> > > > > > > > >> >> >>> > > crude
> > > > > > > > >> >> >>> > > > > > >>> > >> experiments I
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> didn't get
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     a good perf
> > benefit
> > > > from
> > > > > > it
> > > > > > > on
> > > > > > > > >> >> >>> Graviton3
> > > > > > > > >> >> >>> > > (but
> > > > > > > > >> >> >>> > > > > > maybe
> > > > > > > > >> >> >>> > > > > > >>> > there
> > > > > > > > >> >> >>> > > > > > >>> > >> was
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> something
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     wrong with my
> > > > > > > implementation).
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Locking the
> > 16bit
> > > > > > > exception
> > > > > > > > >> >> >>> encoding for
> > > > > > > > >> >> >>> > > the
> > > > > > > > >> >> >>> > > > > > spec
> > > > > > > > >> >> >>> > > > > > >>> in
> > > > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> case.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Awesome I
> think
> > we
> > > > > have
> > > > > > > > solved
> > > > > > > > >> >> for
> > > > > > > > >> >> >>> all
> > > > > > > > >> >> >>> > > open
> > > > > > > > >> >> >>> > > > > > >>> questions
> > > > > > > > >> >> >>> > > > > > >>> > >> minus
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     version byte :).
> > > (will
> > > > > get
> > > > > > > > back
> > > > > > > > >> on
> > > > > > > > >> >> >>> this
> > > > > > > > >> >> >>> > > soon)
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 3) Micah
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - FastLanes :
> The
> > > > > current
> > > > > > > spec
> > > > > > > > >> does
> > > > > > > > >> >> >>> allow
> > > > > > > > >> >> >>> > > for
> > > > > > > > >> >> >>> > > > > > using
> > > > > > > > >> >> >>> > > > > > >>> > >> FastLane
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> with the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     configurable
> enum
> > > > value
> > > > > > for
> > > > > > > > >> >> layout. We
> > > > > > > > >> >> >>> > > should
> > > > > > > > >> >> >>> > > > be
> > > > > > > > >> >> >>> > > > > > >>> able to
> > > > > > > > >> >> >>> > > > > > >>> > >> > inject
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> any
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> layout
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     in the current
> > > design.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Working on resolving
> > all
> > > > > > > remaining
> > > > > > > > >> open
> > > > > > > > >> >> >>> > comments
> > > > > > > > >> >> >>> > > > on
> > > > > > > > >> >> >>> > > > > > the
> > > > > > > > >> >> >>> > > > > > >>> spec
> > > > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> week.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10, 2026
> > at
> > > > > > 3:37 AM
> > > > > > > > >> Steve
> > > > > > > > >> >> >>> > Loughran <
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> stevel@cloudera.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb 2026
> at
> > > > > 18:12,
> > > > > > > > Micah
> > > > > > > > >> >> >>> Kornfield
> > > > > > > > >> >> >>> > <
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> emkornfield@gmail.com>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like the
> > > actual
> > > > > > issue
> > > > > > > > >> >> >>> described for
> > > > > > > > >> >> >>> > > ORC
> > > > > > > > >> >> >>> > > > > in
> > > > > > > > >> >> >>> > > > > > >>> the
> > > > > > > > >> >> >>> > > > > > >>> > >> paper
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
> > > > sub-encodings
> > > > > > in
> > > > > > > a
> > > > > > > > >> >> batch.
> > > > > > > > >> >> >>> This
> > > > > > > > >> >> >>> > > is
> > > > > > > > >> >> >>> > > > > > >>> different
> > > > > > > > >> >> >>> > > > > > >>> > >> then
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here
> where
> > > > there
> > > > > is
> > > > > > > > still
> > > > > > > > >> >> fixed
> > > > > > > > >> >> >>> > > > encoding
> > > > > > > > >> >> >>> > > > > > per
> > > > > > > > >> >> >>> > > > > > >>> page
> > > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given reasonably
> > sized
> > > > > > pages I
> > > > > > > > >> don't
> > > > > > > > >> >> >>> think
> > > > > > > > >> >> >>> > > > branch
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction should
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for new
> > > > > encodings.
> > > > > > > I
> > > > > > > > >> agree
> > > > > > > > >> >> >>> that
> > > > > > > > >> >> >>> > we
> > > > > > > > >> >> >>> > > > > should
> > > > > > > > >> >> >>> > > > > > >>> be
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for adding
> > new
> > > > > > > > encodings.
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > > >> >> >>> > > > > > >>>
> > > > > > > > >> >> >>> > > > > > >>
> > > > > > > > >> >> >>> > > > > >
> > > > > > > > >> >> >>> > > > >
> > > > > > > > >> >> >>> > > >
> > > > > > > > >> >> >>> > >
> > > > > > > > >> >> >>> >
> > > > > > > > >> >> >>>
> > > > > > > > >> >> >>
> > > > > > > > >> >>
> > > > > > > > >> >
> > > > > > > > >>
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [Parquet] ALP Encoding for Floating point data

[Vinoo Ganesh <vi...@gmail.com>]

Thanks everyone!

Thanks,
Vinoo Ganesh | vinoo.ganesh@gmail.com

<Vi...@gmail.com>


On Mon, Nov 9, 2026 at 2:49 PM Andrew Lamb <an...@gmail.com> wrote:

> The Java implementation was just merged[1]!
>
> Thank you Gang, Vinoo, Prateek and everyone who helped push that one along
>
> Andrew
>
> [1]: https://github.com/apache/parquet-java/pull/3397#event-35545451335
>
> On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <pr...@gmail.com> wrote:
>
> > Hi team,
> >
> > Quick update re: the C++ implementation.
> > Thanks to all the reviewers, we merged the C++ implementation today.
> > There are a few follow-up items that I'll address in a subsequent PR.
> >
> > Thanks
> > Prateek
> >
> > On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <vi...@gmail.com>
> > wrote:
> >
> > > Quick update re: the Java impl. Thanks for the feedback, on
> > > https://github.com/apache/parquet-java/pull/3397, Russel! I pulled
> > > https://github.com/apache/parquet-java/pull/3791 into its own PR
> (thanks
> > > for the quick approval too, Gang). Assuming no objections, I think we
> can
> > > merge #3791, and then go ahead of #3397.
> > >
> > > Thanks,
> > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > >
> > > <Vi...@gmail.com>
> > >
> > >
> > > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <pr...@gmail.com>
> wrote:
> > >
> > > > [Rust] Awesome thanks Andrew, Kostas and Devin.
> > > > [Java] Thanks Gang for the feedback on Java PR.
> > > > [C++] Thanks Gang for another round of feedback on the C++ one.
> > > > [Go] Arnav and I will be working on the golang impl this week.
> > > >
> > > > This is great progress all around.
> > > >
> > > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <vi...@gmail.com>
> > > > wrote:
> > > >
> > > > > Thanks all - I'm addressing Gang's comments on
> > > > > https://github.com/apache/parquet-java/pull/3397 now, so hopefully
> > > well
> > > > > also be in a good state for merging the java implementation soon.
> > > > >
> > > > > Thanks,
> > > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > > >
> > > > > <Vi...@gmail.com>
> > > > >
> > > > >
> > > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <andrewlamb11@gmail.com
> >
> > > > wrote:
> > > > >
> > > > > > We just merged the Rust implementation[1] from Kosta and Devan.
> > With
> > > > the
> > > > > > imminent release of Parquet Format 2.14.0 I think we'll be well
> on
> > > our
> > > > > way.
> > > > > >
> > > > > > Thanks again for pushing this along,
> > > > > > Andrew
> > > > > >
> > > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> > > > > >
> > > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <pr...@gmail.com>
> > > > wrote:
> > > > > >
> > > > > > > Hi team,
> > > > > > >
> > > > > > > Thanks Micah for multiple rounds of review and thanks Gang for
> > > > taking a
> > > > > > > look at the PR and giving feedback. I've addressed all comments
> > in
> > > > the
> > > > > > PR.
> > > > > > > Looking forward to the next round of feedback (or approval).
> > Would
> > > > like
> > > > > > to
> > > > > > > get it in soon.
> > > > > > >
> > > > > > > https://github.com/apache/arrow/pull/48345/changes
> > > > > > >
> > > > > > > With this done and after talking to Arnav, I plan to spend some
> > > time
> > > > on
> > > > > > the
> > > > > > > ALP implementation in the arrow-go repository helping spread
> the
> > > > > support
> > > > > > to
> > > > > > > more languages.
> > > > > > >
> > > > > > > Best
> > > > > > > Prateek
> > > > > > >
> > > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <
> prtkgaur@gmail.com
> > >
> > > > > wrote:
> > > > > > >
> > > > > > > > Thanks Divjot for bringing it up.
> > > > > > > >
> > > > > > > > I was under the same impression as Russell and Andrew that
> we'd
> > > > have
> > > > > it
> > > > > > > > flag gated.
> > > > > > > > With the new versioning proposal 'preview' might be a good
> tag
> > > for
> > > > > it.
> > > > > > > >
> > > > > > > > Best
> > > > > > > > Prateek
> > > > > > > >
> > > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> > > > andrewlamb11@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1] (using a
> > > > comment
> > > > > > in
> > > > > > > >> the
> > > > > > > >> spec section).
> > > > > > > >>
> > > > > > > >> Russel: That is my understanding as well.
> > > > > > > >>
> > > > > > > >> Hopefully we are able to formalize the versioning process
> > > shortly
> > > > so
> > > > > > we
> > > > > > > >> can
> > > > > > > >> formalize the notion of "preview"
> > > > > > > >>
> > > > > > > >> Andrew
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> [1]: https://github.com/apache/parquet-format/pull/604
> > > > > > > >>
> > > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> > > > > > > >> russell.spitzer@gmail.com>
> > > > > > > >> wrote:
> > > > > > > >>
> > > > > > > >> > I thought we had agreed it would be merged, and features
> > like
> > > > this
> > > > > > > would
> > > > > > > >> > be feature flag gated. So a V-Old writer could always opt
> in
> > > to
> > > > > > using
> > > > > > > >> this
> > > > > > > >> > encoding but that must be a conscious effort if you are
> not
> > > > using
> > > > > > > VNext
> > > > > > > >> of
> > > > > > > >> > Parquet. If you are on V-Next the writer can choose to use
> > ALP
> > > > > > > whenever
> > > > > > > >> it
> > > > > > > >> > likes without user intervention.
> > > > > > > >> >
> > > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via dev <
> > > > > > > >> > dev@parquet.apache.org> wrote:
> > > > > > > >> >
> > > > > > > >> >> Yes, that’s my understanding as well. However, as you
> > noted,
> > > > the
> > > > > > > >> >> versioning
> > > > > > > >> >> discussion is still in early stages and hasn’t prescribed
> > > > > concrete
> > > > > > > >> >> mechanisms yet. If ALP goes into parquet-format 2.14.0,
> > > there’s
> > > > > no
> > > > > > > >> >> indication that it’s in preview or that writers shouldn’t
> > use
> > > > it
> > > > > by
> > > > > > > >> >> default
> > > > > > > >> >> yet. Given that we’ve held off on merging other
> > incompatible
> > > > > > changes
> > > > > > > >> (e.g
> > > > > > > >> >> removal of path_in_schema) until the versioning
> discussion
> > > > > closes,
> > > > > > my
> > > > > > > >> >> preference would be to leave ALP un-merged for the time
> > being
> > > > as
> > > > > > > well.
> > > > > > > >> >>
> > > > > > > >> >> — Div
> > > > > > > >> >>
> > > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> > > > > andrewlamb11@gmail.com>
> > > > > > > >> wrote:
> > > > > > > >> >>
> > > > > > > >> >> > After re-reading Julien's Versioning Proposal, my
> > > > understanding
> > > > > > is
> > > > > > > >> that
> > > > > > > >> >> if
> > > > > > > >> >> > we adopt that system, we will somehow mark ALP in
> > "Preview"
> > > > in
> > > > > > > >> >> > parquet-format for release Version 3.
> > > > > > > >> >> >
> > > > > > > >> >> > The versioning document doesn't seem to proscribe the
> > > > > particular
> > > > > > > >> method
> > > > > > > >> >> > for annotating "preview" features -- I think clearly
> > > marking
> > > > > them
> > > > > > > as
> > > > > > > >> >> such
> > > > > > > >> >> > in parquet.thrift as well as reflecting that on the
> > > > > > > >> >> > https://parquet.apache.org/docs/file-format/versions/
> > page
> > > > > > somehow
> > > > > > > >> >> would
> > > > > > > >> >> > be adequate.
> > > > > > > >> >> >
> > > > > > > >> >> > Andrew
> > > > > > > >> >> >
> > > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> > > > > > > andrewlamb11@gmail.com
> > > > > > > >> >
> > > > > > > >> >> > wrote:
> > > > > > > >> >> >
> > > > > > > >> >> >> In my mind ALP is in the same position as other
> > encodings
> > > > that
> > > > > > > were
> > > > > > > >> >> added
> > > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non
> floating
> > > > point
> > > > > > > types)
> > > > > > > >> >> >>
> > > > > > > >> >> >> That is to say it will be available in the latest open
> > > > source
> > > > > > > >> writers
> > > > > > > >> >> and
> > > > > > > >> >> >> readers, but realistically not widely used in the
> > > ecosystem
> > > > > > where
> > > > > > > >> >> >> compatibility is a concern (a large part)
> > > > > > > >> >> >>
> > > > > > > >> >> >> I view Julian's work[2][3] to gather consensus on how
> to
> > > > name
> > > > > > > >> >> >> combinations of features (e.g. "versions") as the
> > > mechanism
> > > > by
> > > > > > > >> which we
> > > > > > > >> >> >> will accelerate the adoption of this change (along
> with
> > > > other
> > > > > > > >> forward
> > > > > > > >> >> >> incompatible changes) across the ecosystem.
> > > > > > > >> >> >>
> > > > > > > >> >> >> > Will we exclude this change when cutting
> > parquet-format
> > > > > > v2.14.0?
> > > > > > > >> >> >>
> > > > > > > >> >> >> No I don't think so -- I would expect it to go out in
> > the
> > > > next
> > > > > > > >> >> >> parquet-format version as do other changes in the
> spec.
> > > > > > > >> >> >>
> > > > > > > >> >> >> Andrew
> > > > > > > >> >> >>
> > > > > > > >> >> >> [1]:
> > > https://parquet.apache.org/docs/file-format/versions/
> > > > > > > >> >> >> [2]:
> > > > > > > >>
> > > https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> > > > > > > >> >> >> [3]:
> > > > > > > >>
> > > https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> > > > > > > >> >> >>
> > > > > > > >> >> >>
> > > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora via dev <
> > > > > > > >> >> >> dev@parquet.apache.org> wrote:
> > > > > > > >> >> >>
> > > > > > > >> >> >>> Hi Andrew,
> > > > > > > >> >> >>>
> > > > > > > >> >> >>> How does this interact with the ongoing versioning
> > > > > discussion?
> > > > > > > >> Given
> > > > > > > >> >> that
> > > > > > > >> >> >>> new encodings are not forward compatible, I would
> > assume
> > > > ALP
> > > > > is
> > > > > > > >> >> included
> > > > > > > >> >> >>> in
> > > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to me how
> > that
> > > > > works
> > > > > > if
> > > > > > > >> it's
> > > > > > > >> >> >>> merged to the parquet-format master branch now. Will
> we
> > > > > exclude
> > > > > > > >> this
> > > > > > > >> >> >>> change
> > > > > > > >> >> >>> when cutting parquet-format v2.14.0?
> > > > > > > >> >> >>>
> > > > > > > >> >> >>> -- Div
> > > > > > > >> >> >>>
> > > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
> > > > > > > >> andrewlamb11@gmail.com>
> > > > > > > >> >> >>> wrote:
> > > > > > > >> >> >>>
> > > > > > > >> >> >>> > Hello,
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>> > As an update, thanks to the epic work from many
> > > > > contributors,
> > > > > > > >> >> >>> especially
> > > > > > > >> >> >>> > Prateek, I just merged the parquet-format change
> for
> > > > > ALP[1].
> > > > > > We
> > > > > > > >> >> plan to
> > > > > > > >> >> >>> > make additional editorial The remaining items I
> know
> > of
> > > > are
> > > > > > > >> merging
> > > > > > > >> >> the
> > > > > > > >> >> >>> > examples from parquet-testing[2], and then of
> course
> > > the
> > > > > > > various
> > > > > > > >> >> >>> > implementations
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>> > Thanks again everyone. This is a great step forward
> > > > > > > >> >> >>> > Andrew
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>> > [1]:
> > https://github.com/apache/parquet-format/pull/557
> > > > > > > >> >> >>> > [2]:
> > > https://github.com/apache/parquet-testing/pull/100
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le Dem <
> > > > > > > julien@apache.org
> > > > > > > >> >
> > > > > > > >> >> >>> wrote:
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>> > > It was also in my spam folder... :(
> > > > > > > >> >> >>> > > I've seen a bunch of apache list emails go to my
> > spam
> > > > > > > recently.
> > > > > > > >> >> >>> > >
> > > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell Spitzer
> <
> > > > > > > >> >> >>> > > russell.spitzer@gmail.com>
> > > > > > > >> >> >>> > > wrote:
> > > > > > > >> >> >>> > >
> > > > > > > >> >> >>> > > > Yes, my hope was that my vote would kick it out
> > of
> > > > spam
> > > > > > but
> > > > > > > >> we
> > > > > > > >> >> >>> > definitely
> > > > > > > >> >> >>> > > > had two other votes that also went to spam for
> > me.
> > > > > > > >> >> >>> > > >
> > > > > > > >> >> >>> > > > For anyone looking the thread is here
> > > > > > > >> >> >>> > > >
> > > > > > > >> >>
> > > > https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> > > > > > > >> >> >>> > > >
> > > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah
> Kornfield
> > <
> > > > > > > >> >> >>> > emkornfield@gmail.com>
> > > > > > > >> >> >>> > > > wrote:
> > > > > > > >> >> >>> > > >
> > > > > > > >> >> >>> > > > > I've seen other's votes not go to spam, so
> > > > hopefully
> > > > > > > people
> > > > > > > >> >> will
> > > > > > > >> >> >>> see
> > > > > > > >> >> >>> > it
> > > > > > > >> >> >>> > > > in
> > > > > > > >> >> >>> > > > > there inboxes (or see this thread and look in
> > > there
> > > > > > > spam).
> > > > > > > >> >> >>> > > > >
> > > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM PRATEEK
> GAUR <
> > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > wrote:
> > > > > > > >> >> >>> > > > >
> > > > > > > >> >> >>> > > > > > Okay,
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > > > I sent out the voting email yesterday and
> so
> > > far
> > > > > I've
> > > > > > > >> heard
> > > > > > > >> >> >>> from 3
> > > > > > > >> >> >>> > > > people
> > > > > > > >> >> >>> > > > > > that it ended up in their "spam folder".
> Dev
> > > VPN
> > > > to
> > > > > > be
> > > > > > > >> >> blamed
> > > > > > > >> >> >>> for
> > > > > > > >> >> >>> > > it?.
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > > > What's the protocol here?
> > > > > > > >> >> >>> > > > > > I let people hunt for the email in their
> spam
> > > > > folder
> > > > > > or
> > > > > > > >> send
> > > > > > > >> >> >>> out
> > > > > > > >> >> >>> > > > another
> > > > > > > >> >> >>> > > > > > one?
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > > > Best
> > > > > > > >> >> >>> > > > > > Prateek
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM PRATEEK
> > GAUR <
> > > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > > wrote:
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > > > > Hi team,
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > Vinoo has added the tests which were
> > > requested
> > > > in
> > > > > > the
> > > > > > > >> last
> > > > > > > >> >> >>> round
> > > > > > > >> >> >>> > of
> > > > > > > >> >> >>> > > > > > review.
> > > > > > > >> >> >>> > > > > > > In his own words.
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > "
> > > > > > > >> >> >>> > > > > > > The extreme value tests Micah wanted are
> > done
> > > > and
> > > > > > > >> pushed.
> > > > > > > >> >> I
> > > > > > > >> >> >>> added
> > > > > > > >> >> >>> > > > > > coverage
> > > > > > > >> >> >>> > > > > > > for values that need the full FOR bit
> width
> > > > after
> > > > > > the
> > > > > > > >> >> frame
> > > > > > > >> >> >>> of
> > > > > > > >> >> >>> > > > > reference
> > > > > > > >> >> >>> > > > > > is
> > > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where the
> signed
> > > max
> > > > > > minus
> > > > > > > >> min
> > > > > > > >> >> >>> > > subtraction
> > > > > > > >> >> >>> > > > > > > overflows), 63-bit (the non-overflow
> case),
> > > and
> > > > > > > 32-bit
> > > > > > > >> for
> > > > > > > >> >> >>> > floats.
> > > > > > > >> >> >>> > > > All
> > > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I also
> > > verified
> > > > > them
> > > > > > > >> >> through
> > > > > > > >> >> >>> Arrow
> > > > > > > >> >> >>> > > C++
> > > > > > > >> >> >>> > > > > ALP
> > > > > > > >> >> >>> > > > > > > reader (the local build), so the
> > Java-written
> > > > > > extreme
> > > > > > > >> >> columns
> > > > > > > >> >> >>> > > decode
> > > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact against the
> > > > expected
> > > > > > > >> values."
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > State of the PR (#3397):
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I pulled
> > > > master
> > > > > in
> > > > > > > and
> > > > > > > >> >> >>> resolved
> > > > > > > >> >> >>> > > the
> > > > > > > >> >> >>> > > > > > >    conflicts).
> > > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads resolved.
> The
> > 3
> > > > > > > remaining
> > > > > > > >> are
> > > > > > > >> >> >>> > > > intentional:
> > > > > > > >> >> >>> > > > > > >    one deferred perf nit, one that stays
> > open
> > > > > until
> > > > > > > >> >> >>> > parquet-format
> > > > > > > >> >> >>> > > > > ships
> > > > > > > >> >> >>> > > > > > ALP,
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > "
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > With this both the
> > > > > > > >> >> >>> > > > > > > 1) C++ PR :
> > > > > > > >> >> >>> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > >> >> >>> > > > > > > 2) Java PR :
> > > > > > > >> >> >>> https://github.com/apache/parquet-java/pull/3397
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > Are cross language tested and range of
> test
> > > > > > > scenarios.
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > Best
> > > > > > > >> >> >>> > > > > > > Prateek
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM PRATEEK
> > GAUR
> > > <
> > > > > > > >> >> >>> prtkgaur@gmail.com
> > > > > > > >> >> >>> > >
> > > > > > > >> >> >>> > > > > wrote:
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > >> Thanks Matt,
> > > > > > > >> >> >>> > > > > > >>
> > > > > > > >> >> >>> > > > > > >> I'll be on it this week.
> > > > > > > >> >> >>> > > > > > >>
> > > > > > > >> >> >>> > > > > > >> Best
> > > > > > > >> >> >>> > > > > > >> Prateek
> > > > > > > >> >> >>> > > > > > >>
> > > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM Matt
> > Topol <
> > > > > > > >> >> >>> > > zotthewizard@gmail.com>
> > > > > > > >> >> >>> > > > > > >> wrote:
> > > > > > > >> >> >>> > > > > > >>
> > > > > > > >> >> >>> > > > > > >>> There is also the Go implementation
> > > submitted
> > > > > by
> > > > > > > >> Arnav (
> > > > > > > >> >> >>> > > > > > >>>
> > > https://github.com/apache/arrow-go/pull/704)
> > > > > > which
> > > > > > > >> is
> > > > > > > >> >> >>> waiting
> > > > > > > >> >> >>> > > for
> > > > > > > >> >> >>> > > > > > >>> updates.
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it didn't get
> > lost
> > > > > here.
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>> > > > > > >>> --Matt
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM
> PRATEEK
> > > > GAUR <
> > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>> > > > > > >>> > Hi all,
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > I'd like to share a status update on
> > the
> > > > ALP
> > > > > > > >> encoding
> > > > > > > >> >> >>> effort
> > > > > > > >> >> >>> > > and
> > > > > > > >> >> >>> > > > > get
> > > > > > > >> >> >>> > > > > > a
> > > > > > > >> >> >>> > > > > > >>> feel
> > > > > > > >> >> >>> > > > > > >>> > from the community before starting a
> > > formal
> > > > > > vote.
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > We now have the specification plus
> > > > > > > implementations
> > > > > > > >> in
> > > > > > > >> >> >>> both
> > > > > > > >> >> >>> > > > > languages:
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> >     - Spec:
> > > > >  apache/parquet-format#557 —
> > > > > > > >> GH-533
> > > > > > > >> >> >>> Add
> > > > > > > >> >> >>> > ALP
> > > > > > > >> >> >>> > > > > > encoding
> > > > > > > >> >> >>> > > > > > >>> > specification
> > > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):
> apache/arrow#48345
> > —
> > > > > > GH-48701
> > > > > > > >> >> >>> > > [C++][Parquet]
> > > > > > > >> >> >>> > > > > Add
> > > > > > > >> >> >>> > > > > > >>> ALPpd
> > > > > > > >> >> >>> > > > > > >>> > encoding
> > > > > > > >> >> >>> > > > > > >>> >     - Java:
> > > >  apache/parquet-java#3397
> > > > > —
> > > > > > > >> Parquet
> > > > > > > >> >> >>> Java
> > > > > > > >> >> >>> > ALP
> > > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > Current state:
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation has been
> > > > through
> > > > > > 3-4
> > > > > > > >> >> rounds
> > > > > > > >> >> >>> of
> > > > > > > >> >> >>> > > > review.
> > > > > > > >> >> >>> > > > > > >>> >     - The Java implementation has
> been
> > > > > tracking
> > > > > > > >> well
> > > > > > > >> >> and
> > > > > > > >> >> >>> has
> > > > > > > >> >> >>> > > had
> > > > > > > >> >> >>> > > > > > >>> initial
> > > > > > > >> >> >>> > > > > > >>> >       reviews from contributors, with
> > no
> > > > > major
> > > > > > > >> >> remaining
> > > > > > > >> >> >>> > > issues.
> > > > > > > >> >> >>> > > > > > >>> >     - Cross-language compatibility
> > tests
> > > > are
> > > > > > > >> passing:
> > > > > > > >> >> the
> > > > > > > >> >> >>> > Arrow
> > > > > > > >> >> >>> > > > C++
> > > > > > > >> >> >>> > > > > > >>> decoder
> > > > > > > >> >> >>> > > > > > >>> >       reads Java-written data
> > bit-exactly
> > > > > > across
> > > > > > > >> >> ~1.56M
> > > > > > > >> >> >>> > values
> > > > > > > >> >> >>> > > > and
> > > > > > > >> >> >>> > > > > 18
> > > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1 and V2
> > pages,
> > > > > > > multiple
> > > > > > > >> >> vector
> > > > > > > >> >> >>> > > sizes,
> > > > > > > >> >> >>> > > > > and
> > > > > > > >> >> >>> > > > > > >>> > several
> > > > > > > >> >> >>> > > > > > >>> >       real datasets — zero
> mismatches.
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we will be
> > > adding
> > > > > > > >> coverage
> > > > > > > >> >> for
> > > > > > > >> >> >>> > > extreme
> > > > > > > >> >> >>> > > > > > values
> > > > > > > >> >> >>> > > > > > >>> > (those requiring
> > > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is applied)
> > before
> > > we
> > > > > > > close a
> > > > > > > >> >> vote.
> > > > > > > >> >> >>> > We'll
> > > > > > > >> >> >>> > > > aim
> > > > > > > >> >> >>> > > > > > to
> > > > > > > >> >> >>> > > > > > >>> get
> > > > > > > >> >> >>> > > > > > >>> > that
> > > > > > > >> >> >>> > > > > > >>> >  done in parallel.
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > Plan: unless there are objections, I
> > > intend
> > > > > to
> > > > > > > >> start a
> > > > > > > >> >> >>> vote
> > > > > > > >> >> >>> > at
> > > > > > > >> >> >>> > > > the
> > > > > > > >> >> >>> > > > > > end
> > > > > > > >> >> >>> > > > > > >>> of
> > > > > > > >> >> >>> > > > > > >>> > this week/early
> > > > > > > >> >> >>> > > > > > >>> > next week.
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > Thanks
> > > > > > > >> >> >>> > > > > > >>> > Prateek
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM
> PRATEEK
> > > > GAUR <
> > > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>> > > Hi Team,
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some updates
> > on
> > > > ALP.
> > > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4 rounds of
> > > > review
> > > > > > for
> > > > > > > >> the
> > > > > > > >> >> c++
> > > > > > > >> >> >>> PR :
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > https://github.com/apache/arrow/pull/48345
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> > > For the Java implementation Vinoo
> has
> > > > been
> > > > > > > >> working
> > > > > > > >> >> on
> > > > > > > >> >> >>> > > following
> > > > > > > >> >> >>> > > > > PR
> > > > > > > >> >> >>> > > > > > :
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > https://github.com/apache/parquet-java/pull/3397
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> > > Best
> > > > > > > >> >> >>> > > > > > >>> > > Prateek
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at 1:50 PM
> Micah
> > > > > > Kornfield
> > > > > > > <
> > > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > > wrote:
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> > > already
> > > > > > asked,
> > > > > > > >> but
> > > > > > > >> >> >>> should
> > > > > > > >> >> >>> > we
> > > > > > > >> >> >>> > > > > care
> > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT + ALP
> > be
> > > > more
> > > > > > > >> >> efficient
> > > > > > > >> >> >>> than
> > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > >> >> >>> > > > > > +
> > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> > example?
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we could defer
> > it
> > > > for
> > > > > > the
> > > > > > > >> >> >>> following
> > > > > > > >> >> >>> > > > reasons:
> > > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there are a lot
> > of
> > > > easy
> > > > > > > >> >> reference
> > > > > > > >> >> >>> > > datasets
> > > > > > > >> >> >>> > > > to
> > > > > > > >> >> >>> > > > > > >>> test
> > > > > > > >> >> >>> > > > > > >>> > its
> > > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does look like
> > > there
> > > > > > might
> > > > > > > be
> > > > > > > >> >> one
> > > > > > > >> >> >>> or
> > > > > > > >> >> >>> > two
> > > > > > > >> >> >>> > > on
> > > > > > > >> >> >>> > > > > > >>> > huggingface
> > > > > > > >> >> >>> > > > > > >>> > >> (e.g.
> > > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> > > > > > > >> >> >>> ).
> > > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that float 16
> > was
> > > > > more
> > > > > > > >> likely
> > > > > > > >> >> >>> used
> > > > > > > >> >> >>> > for
> > > > > > > >> >> >>> > > > > values
> > > > > > > >> >> >>> > > > > > >>> that
> > > > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce to
> > decimal
> > > > > > values.
> > > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an
> > extension
> > > > > later
> > > > > > if
> > > > > > > >> >> needed.
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> Cheers,
> > > > > > > >> >> >>> > > > > > >>> > >> Micah
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at 1:40 PM
> > Antoine
> > > > > > Pitrou
> > > > > > > <
> > > > > > > >> >> >>> > > > > antoine@python.org
> > > > > > > >> >> >>> > > > > > >
> > > > > > > >> >> >>> > > > > > >>> > wrote:
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > Hello,
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> > > already
> > > > > > asked,
> > > > > > > >> but
> > > > > > > >> >> >>> should
> > > > > > > >> >> >>> > we
> > > > > > > >> >> >>> > > > > care
> > > > > > > >> >> >>> > > > > > >>> about
> > > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT + ALP
> > be
> > > > more
> > > > > > > >> >> efficient
> > > > > > > >> >> >>> than
> > > > > > > >> >> >>> > > > > FLOAT16
> > > > > > > >> >> >>> > > > > > +
> > > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> > example?
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > Regards
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10, PRATEEK
> > GAUR
> > > a
> > > > > > écrit
> > > > > > > :
> > > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah for
> > review
> > > > > > > feedback
> > > > > > > >> on
> > > > > > > >> >> >>> the two
> > > > > > > >> >> >>> > > > PR's
> > > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> https://github.com/apache/arrow/pull/48345/changes
> > > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format repo)
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> https://github.com/apache/parquet-format/pull/557
> > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all (unless I
> > > > missed
> > > > > > > >> >> something)
> > > > > > > >> >> >>> > > comments
> > > > > > > >> >> >>> > > > on
> > > > > > > >> >> >>> > > > > > >>> the two
> > > > > > > >> >> >>> > > > > > >>> > >> > PR's.
> > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > >> >> >>> > > > > > >>> > >> > > Best
> > > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at
> 1:08 PM
> > > > > PRATEEK
> > > > > > > >> GAUR <
> > > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > >> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and Micah.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of feedback on
> at
> > > > least
> > > > > > the
> > > > > > > >> >> >>> > > implementations`
> > > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have already
> > > started
> > > > > > > >> addressing
> > > > > > > >> >> the
> > > > > > > >> >> >>> > > > > feedback, I
> > > > > > > >> >> >>> > > > > > >>> > should
> > > > > > > >> >> >>> > > > > > >>> > >> be
> > > > > > > >> >> >>> > > > > > >>> > >> > >> done with that
> Monday/Tuesday.
> > > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has been
> > making
> > > > > good
> > > > > > > >> >> progress
> > > > > > > >> >> >>> on
> > > > > > > >> >> >>> > the
> > > > > > > >> >> >>> > > > Java
> > > > > > > >> >> >>> > > > > > >>> > >> > implementation.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> > >> Best
> > > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026 at
> > 12:55 PM
> > > > > Andrew
> > > > > > > >> Lamb <
> > > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for the
> > > > > > clarification
> > > > > > > >> -- I
> > > > > > > >> >> >>> will
> > > > > > > >> >> >>> > try
> > > > > > > >> >> >>> > > > and
> > > > > > > >> >> >>> > > > > > look
> > > > > > > >> >> >>> > > > > > >>> > into
> > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> > > > implementation[1]
> > > > > in
> > > > > > > >> this
> > > > > > > >> >> next
> > > > > > > >> >> >>> > week
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> > > > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026 at
> > 12:01 PM
> > > > > Micah
> > > > > > > >> >> >>> Kornfield <
> > > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a fair
> > amount
> > > of
> > > > > > > >> feedback
> > > > > > > >> >> on
> > > > > > > >> >> >>> at
> > > > > > > >> >> >>> > > least
> > > > > > > >> >> >>> > > > > the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations, typically
> I
> > > > think
> > > > > > > we've
> > > > > > > >> >> waited
> > > > > > > >> >> >>> > till
> > > > > > > >> >> >>> > > > they
> > > > > > > >> >> >>> > > > > > are
> > > > > > > >> >> >>> > > > > > >>> > >> close to
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a final
> > vote.
> > > > > > > >> Otherwise I
> > > > > > > >> >> >>> agree
> > > > > > > >> >> >>> > we
> > > > > > > >> >> >>> > > > are
> > > > > > > >> >> >>> > > > > > very
> > > > > > > >> >> >>> > > > > > >>> > >> close.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April 25,
> 2026,
> > > > Andrew
> > > > > > > Lamb
> > > > > > > >> <
> > > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> > >> > wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this content
> it
> > > > looks
> > > > > > to
> > > > > > > me
> > > > > > > >> >> like
> > > > > > > >> >> >>> we
> > > > > > > >> >> >>> > are
> > > > > > > >> >> >>> > > > > ready
> > > > > > > >> >> >>> > > > > > >>> to
> > > > > > > >> >> >>> > > > > > >>> > >> start a
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly accept
> > ALP
> > > > into
> > > > > > > >> Parquet
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know of a
> reason
> > > we
> > > > > > should
> > > > > > > >> >> >>> postpone it
> > > > > > > >> >> >>> > > for
> > > > > > > >> >> >>> > > > > > >>> longer?
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone needs some
> > > more
> > > > > time
> > > > > > > to
> > > > > > > >> >> >>> review?
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22, 2026 at
> > > 1:00 PM
> > > > > > > PRATEEK
> > > > > > > >> >> GAUR <
> > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is doing
> > well.
> > > I
> > > > > got
> > > > > > a
> > > > > > > >> >> chance
> > > > > > > >> >> >>> to
> > > > > > > >> >> >>> > work
> > > > > > > >> >> >>> > > > > > >>> through all
> > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback and
> > update
> > > > the
> > > > > > > spec
> > > > > > > >> >> doc.
> > > > > > > >> >> >>> Here
> > > > > > > >> >> >>> > > are
> > > > > > > >> >> >>> > > > > the
> > > > > > > >> >> >>> > > > > > >>> new
> > > > > > > >> >> >>> > > > > > >>> > >> > artifacts
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > >
> > > > > > > >> >> >>> > > >
> > > > > > > >> >> >>> > >
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>>
> > > > > > > >> >>
> > > > > > > >>
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-
> 3fPtD_aWt/edit
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document in
> parquet
> > > > > format
> > > > > > > >> repo :
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > https://github.com/apache/parquet-format/pull/557
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp implementation in
> > > arrow
> > > > > c++
> > > > > > > >> repo :
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > https://github.com/apache/arrow/pull/48345/changes
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp implementation in
> > > > > > parquet-java
> > > > > > > >> >> repo :
> > > > > > > >> >> >>> Work
> > > > > > > >> >> >>> > > for
> > > > > > > >> >> >>> > > > > > >>> Vinoo and
> > > > > > > >> >> >>> > > > > > >>> > >> > Julien
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > https://github.com/apache/parquet-java/pull/3397
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test and
> > > > benchmarking
> > > > > > > >> >> artifacts in
> > > > > > > >> >> >>> > > > > > >>> parquet-testing
> > > > > > > >> >> >>> > > > > > >>> > >> repo :
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > https://github.com/apache/parquet-testing/pull/100
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav just
> > > submitted
> > > > > an
> > > > > > in
> > > > > > > >> >> >>> progress
> > > > > > > >> >> >>> > > > > > >>> implementation
> > > > > > > >> >> >>> > > > > > >>> > in
> > > > > > > >> >> >>> > > > > > >>> > >> Go.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> https://github.com/apache/arrow-go/pull/704
> > > > > > > >> >> >>> > (I
> > > > > > > >> >> >>> > > > > > haven't
> > > > > > > >> >> >>> > > > > > >>> > >> started
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     looking at it yet)
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Rust : I remember
> > > Andrew
> > > > > > > >> mentioned
> > > > > > > >> >> that
> > > > > > > >> >> >>> > this
> > > > > > > >> >> >>> > > > work
> > > > > > > >> >> >>> > > > > > is
> > > > > > > >> >> >>> > > > > > >>> also
> > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     progress (So 4
> > > languages!)
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Arrow C++
> implementation *
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> The PR is out and was
> also
> > > used
> > > > > by
> > > > > > > >> >> Antoine to
> > > > > > > >> >> >>> > > report
> > > > > > > >> >> >>> > > > > the
> > > > > > > >> >> >>> > > > > > >>> > numbers
> > > > > > > >> >> >>> > > > > > >>> > >> as
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> reported here. Micah and
> > > > > Konstantin
> > > > > > > >> have
> > > > > > > >> >> >>> given 1
> > > > > > > >> >> >>> > > > round
> > > > > > > >> >> >>> > > > > of
> > > > > > > >> >> >>> > > > > > >>> > >> feedback
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> and I'm addressing them
> > > today.
> > > > > > Please
> > > > > > > >> note
> > > > > > > >> >> >>> that
> > > > > > > >> >> >>> > the
> > > > > > > >> >> >>> > > > > > default
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> optimization flag for
> > > compiling
> > > > > is
> > > > > > O2
> > > > > > > >> and
> > > > > > > >> >> not
> > > > > > > >> >> >>> > Q3. I
> > > > > > > >> >> >>> > > > got
> > > > > > > >> >> >>> > > > > > >>> around
> > > > > > > >> >> >>> > > > > > >>> > >> 70%
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> performance improvement
> in
> > > the
> > > > > > > decoding
> > > > > > > >> >> speed
> > > > > > > >> >> >>> > when
> > > > > > > >> >> >>> > > > > using
> > > > > > > >> >> >>> > > > > > >>> the O3
> > > > > > > >> >> >>> > > > > > >>> > >> > flag.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Parqet-MR Java
> > > implementation
> > > > > > > (working
> > > > > > > >> >> with
> > > > > > > >> >> >>> > Vinoo
> > > > > > > >> >> >>> > > > and
> > > > > > > >> >> >>> > > > > > >>> Julien)
> > > > > > > >> >> >>> > > > > > >>> > >> and
> > > > > > > >> >> >>> > > > > > >>> > >> > **Cross
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Language testing*
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     Let me know if you
> have
> > > any
> > > > > > > >> questions
> > > > > > > >> >> or
> > > > > > > >> >> >>> > > > feedback.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Now pasting some
> > performance
> > > > > > numbers
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    Table 1: C++ ALP
> Double
> > > > > Decode —
> > > > > > > >> >> Spotify
> > > > > > > >> >> >>> > Columns
> > > > > > > >> >> >>> > > > > > >>> (Graviton
> > > > > > > >> >> >>> > > > > > >>> > 3,
> > > > > > > >> >> >>> > > > > > >>> > >> ARM
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Neoverse V1)
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>>
> > > > ┌──────────────────┬──────────────┬──────────────┬─────────┐
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ Column           │
> > -O2
> > > > > (MB/s)
> > > > > > > │
> > > > > > > >> >> -O3
> > > > > > > >> >> >>> > > (MB/s)  │
> > > > > > > >> >> >>> > > > > > >>> Speedup │
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>>
> > > > ├──────────────────┼──────────────┼──────────────┼─────────┤
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ valence          │
> > > >  3,155
> > > > > > > │
> > > > > > > >> >> >>>  5,523
> > > > > > > >> >> >>> > >   │
> > > > > > > >> >> >>> > > > > > >>> 1.75x  │
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ danceability     │
> > > >  3,233
> > > > > > > │
> > > > > > > >> >> >>>  5,685
> > > > > > > >> >> >>> > >   │
> > > > > > > >> >> >>> > > > > > >>> 1.76x  │
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ energy           │
> > > >  3,197
> > > > > > > │
> > > > > > > >> >> >>>  5,652
> > > > > > > >> >> >>> > >   │
> > > > > > > >> >> >>> > > > > > >>> 1.77x  │
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ loudness         │
> > > >  3,186
> > > > > > > │
> > > > > > > >> >> >>>  5,473
> > > > > > > >> >> >>> > >   │
> > > > > > > >> >> >>> > > > > > >>> 1.72x  │
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>>
> > > > └──────────────────┴──────────────┴──────────────┴─────────┘
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> On Wed, Feb 25, 2026 at
> > > 9:49 AM
> > > > > > > PRATEEK
> > > > > > > >> >> GAUR
> > > > > > > >> >> >>> <
> > > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Micah Kornfield <
> > > > > > > >> emkornfield@gmail.com>
> > > > > > > >> >> :
> > > > > > > >> >> >>> Got
> > > > > > > >> >> >>> > > it.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Andrew Lamb <
> > > > > > > andrewlamb11@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Do you think it would
> be
> > > good
> > > > > to
> > > > > > > >> start
> > > > > > > >> >> >>> moving
> > > > > > > >> >> >>> > the
> > > > > > > >> >> >>> > > > > spec
> > > > > > > >> >> >>> > > > > > >>> > >> development
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> into
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> markdown format, in
> > > > preparation
> > > > > > for
> > > > > > > >> >> >>> finalizing
> > > > > > > >> >> >>> > > it?
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Yes I'll update the
> > numbers
> > > > for
> > > > > > some
> > > > > > > >> of
> > > > > > > >> >> the
> > > > > > > >> >> >>> > > > examples I
> > > > > > > >> >> >>> > > > > > >>> have in
> > > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> spec based
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> on the updated header
> > size.
> > > > Then
> > > > > > we
> > > > > > > >> >> should
> > > > > > > >> >> >>> be
> > > > > > > >> >> >>> > good
> > > > > > > >> >> >>> > > > to
> > > > > > > >> >> >>> > > > > go
> > > > > > > >> >> >>> > > > > > >>> for
> > > > > > > >> >> >>> > > > > > >>> > the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> markdown format.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Thanks everyone!
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Andrew
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> On Tue, Feb 17, 2026 at
> > > > 7:28 PM
> > > > > > > >> PRATEEK
> > > > > > > >> >> >>> GAUR <
> > > > > > > >> >> >>> > > > > > >>> > >> prtkgaur@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Hi team,
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 1) Andrew
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> working
> > > on
> > > > > test
> > > > > > > >> files.
> > > > > > > >> >> >>> My PR
> > > > > > > >> >> >>> > > did
> > > > > > > >> >> >>> > > > > add
> > > > > > > >> >> >>> > > > > > >>> all
> > > > > > > >> >> >>> > > > > > >>> > the
> > > > > > > >> >> >>> > > > > > >>> > >> > test
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> files I
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     used to benchmark
> on
> > > > > > datasets.
> > > > > > > >> >> Maybe
> > > > > > > >> >> >>> we
> > > > > > > >> >> >>> > can
> > > > > > > >> >> >>> > > > club
> > > > > > > >> >> >>> > > > > > it
> > > > > > > >> >> >>> > > > > > >>> > >> together.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> WIll also
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> aid
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     cross language
> > testing
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     -  Kosta Tarasov
> > > working
> > > > > on
> > > > > > > Rust
> > > > > > > >> >> >>> > > > implementation.
> > > > > > > >> >> >>> > > > > > >>> This is
> > > > > > > >> >> >>> > > > > > >>> > >> > great.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Thanks
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 2) Antoine
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks a lot for
> > > > > reporting
> > > > > > > the
> > > > > > > >> >> >>> numbers
> > > > > > > >> >> >>> > on
> > > > > > > >> >> >>> > > > AMD.
> > > > > > > >> >> >>> > > > > > >>> Looks
> > > > > > > >> >> >>> > > > > > >>> > >> like
> > > > > > > >> >> >>> > > > > > >>> > >> > you
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> are
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     getting 8X the
> > > decoding
> > > > > > > >> >> performance of
> > > > > > > >> >> >>> > BSS.
> > > > > > > >> >> >>> > > > This
> > > > > > > >> >> >>> > > > > > is
> > > > > > > >> >> >>> > > > > > >>> > >> > amazing!!.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > > > acknowledging
> > > > > > the
> > > > > > > >> >> >>> sampling
> > > > > > > >> >> >>> > > > design.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - I agree with you
> > on
> > > > > > > >> Fastlanes. In
> > > > > > > >> >> >>> some
> > > > > > > >> >> >>> > > crude
> > > > > > > >> >> >>> > > > > > >>> > >> experiments I
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> didn't get
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     a good perf
> benefit
> > > from
> > > > > it
> > > > > > on
> > > > > > > >> >> >>> Graviton3
> > > > > > > >> >> >>> > > (but
> > > > > > > >> >> >>> > > > > > maybe
> > > > > > > >> >> >>> > > > > > >>> > there
> > > > > > > >> >> >>> > > > > > >>> > >> was
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> something
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     wrong with my
> > > > > > implementation).
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Locking the
> 16bit
> > > > > > exception
> > > > > > > >> >> >>> encoding for
> > > > > > > >> >> >>> > > the
> > > > > > > >> >> >>> > > > > > spec
> > > > > > > >> >> >>> > > > > > >>> in
> > > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> case.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Awesome I think
> we
> > > > have
> > > > > > > solved
> > > > > > > >> >> for
> > > > > > > >> >> >>> all
> > > > > > > >> >> >>> > > open
> > > > > > > >> >> >>> > > > > > >>> questions
> > > > > > > >> >> >>> > > > > > >>> > >> minus
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     version byte :).
> > (will
> > > > get
> > > > > > > back
> > > > > > > >> on
> > > > > > > >> >> >>> this
> > > > > > > >> >> >>> > > soon)
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 3) Micah
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - FastLanes : The
> > > > current
> > > > > > spec
> > > > > > > >> does
> > > > > > > >> >> >>> allow
> > > > > > > >> >> >>> > > for
> > > > > > > >> >> >>> > > > > > using
> > > > > > > >> >> >>> > > > > > >>> > >> FastLane
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> with the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     configurable enum
> > > value
> > > > > for
> > > > > > > >> >> layout. We
> > > > > > > >> >> >>> > > should
> > > > > > > >> >> >>> > > > be
> > > > > > > >> >> >>> > > > > > >>> able to
> > > > > > > >> >> >>> > > > > > >>> > >> > inject
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> any
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> layout
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     in the current
> > design.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Working on resolving
> all
> > > > > > remaining
> > > > > > > >> open
> > > > > > > >> >> >>> > comments
> > > > > > > >> >> >>> > > > on
> > > > > > > >> >> >>> > > > > > the
> > > > > > > >> >> >>> > > > > > >>> spec
> > > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> week.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10, 2026
> at
> > > > > 3:37 AM
> > > > > > > >> Steve
> > > > > > > >> >> >>> > Loughran <
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> stevel@cloudera.com>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb 2026 at
> > > > 18:12,
> > > > > > > Micah
> > > > > > > >> >> >>> Kornfield
> > > > > > > >> >> >>> > <
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> emkornfield@gmail.com>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like the
> > actual
> > > > > issue
> > > > > > > >> >> >>> described for
> > > > > > > >> >> >>> > > ORC
> > > > > > > >> >> >>> > > > > in
> > > > > > > >> >> >>> > > > > > >>> the
> > > > > > > >> >> >>> > > > > > >>> > >> paper
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
> > > sub-encodings
> > > > > in
> > > > > > a
> > > > > > > >> >> batch.
> > > > > > > >> >> >>> This
> > > > > > > >> >> >>> > > is
> > > > > > > >> >> >>> > > > > > >>> different
> > > > > > > >> >> >>> > > > > > >>> > >> then
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here where
> > > there
> > > > is
> > > > > > > still
> > > > > > > >> >> fixed
> > > > > > > >> >> >>> > > > encoding
> > > > > > > >> >> >>> > > > > > per
> > > > > > > >> >> >>> > > > > > >>> page
> > > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given reasonably
> sized
> > > > > pages I
> > > > > > > >> don't
> > > > > > > >> >> >>> think
> > > > > > > >> >> >>> > > > branch
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction should
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for new
> > > > encodings.
> > > > > > I
> > > > > > > >> agree
> > > > > > > >> >> >>> that
> > > > > > > >> >> >>> > we
> > > > > > > >> >> >>> > > > > should
> > > > > > > >> >> >>> > > > > > >>> be
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for adding
> new
> > > > > > > encodings.
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > > >> >> >>> > > > > > >>> > >
> > > > > > > >> >> >>> > > > > > >>> >
> > > > > > > >> >> >>> > > > > > >>>
> > > > > > > >> >> >>> > > > > > >>
> > > > > > > >> >> >>> > > > > >
> > > > > > > >> >> >>> > > > >
> > > > > > > >> >> >>> > > >
> > > > > > > >> >> >>> > >
> > > > > > > >> >> >>> >
> > > > > > > >> >> >>>
> > > > > > > >> >> >>
> > > > > > > >> >>
> > > > > > > >> >
> > > > > > > >>
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [Parquet] ALP Encoding for Floating point data

[Andrew Lamb <an...@gmail.com>]

The Java implementation was just merged[1]!

Thank you Gang, Vinoo, Prateek and everyone who helped push that one along

Andrew

[1]: https://github.com/apache/parquet-java/pull/3397#event-35545451335

On Tue, Oct 13, 2026 at 12:52 PM PRATEEK GAUR <pr...@gmail.com> wrote:

> Hi team,
>
> Quick update re: the C++ implementation.
> Thanks to all the reviewers, we merged the C++ implementation today.
> There are a few follow-up items that I'll address in a subsequent PR.
>
> Thanks
> Prateek
>
> On Sun, Sep 13, 2026 at 6:54 PM Vinoo Ganesh <vi...@gmail.com>
> wrote:
>
> > Quick update re: the Java impl. Thanks for the feedback, on
> > https://github.com/apache/parquet-java/pull/3397, Russel! I pulled
> > https://github.com/apache/parquet-java/pull/3791 into its own PR (thanks
> > for the quick approval too, Gang). Assuming no objections, I think we can
> > merge #3791, and then go ahead of #3397.
> >
> > Thanks,
> > Vinoo Ganesh | vinoo.ganesh@gmail.com
> >
> > <Vi...@gmail.com>
> >
> >
> > On Tue, Sep 8, 2026 at 10:54 AM PRATEEK GAUR <pr...@gmail.com> wrote:
> >
> > > [Rust] Awesome thanks Andrew, Kostas and Devin.
> > > [Java] Thanks Gang for the feedback on Java PR.
> > > [C++] Thanks Gang for another round of feedback on the C++ one.
> > > [Go] Arnav and I will be working on the golang impl this week.
> > >
> > > This is great progress all around.
> > >
> > > On Sat, Sep 5, 2026 at 1:26 PM Vinoo Ganesh <vi...@gmail.com>
> > > wrote:
> > >
> > > > Thanks all - I'm addressing Gang's comments on
> > > > https://github.com/apache/parquet-java/pull/3397 now, so hopefully
> > well
> > > > also be in a good state for merging the java implementation soon.
> > > >
> > > > Thanks,
> > > > Vinoo Ganesh | vinoo.ganesh@gmail.com
> > > >
> > > > <Vi...@gmail.com>
> > > >
> > > >
> > > > On Sat, Sep 5, 2026 at 8:56 AM Andrew Lamb <an...@gmail.com>
> > > wrote:
> > > >
> > > > > We just merged the Rust implementation[1] from Kosta and Devan.
> With
> > > the
> > > > > imminent release of Parquet Format 2.14.0 I think we'll be well on
> > our
> > > > way.
> > > > >
> > > > > Thanks again for pushing this along,
> > > > > Andrew
> > > > >
> > > > > [1]: https://github.com/apache/arrow-rs/pull/9372
> > > > >
> > > > > On Fri, Sep 4, 2026 at 5:42 PM PRATEEK GAUR <pr...@gmail.com>
> > > wrote:
> > > > >
> > > > > > Hi team,
> > > > > >
> > > > > > Thanks Micah for multiple rounds of review and thanks Gang for
> > > taking a
> > > > > > look at the PR and giving feedback. I've addressed all comments
> in
> > > the
> > > > > PR.
> > > > > > Looking forward to the next round of feedback (or approval).
> Would
> > > like
> > > > > to
> > > > > > get it in soon.
> > > > > >
> > > > > > https://github.com/apache/arrow/pull/48345/changes
> > > > > >
> > > > > > With this done and after talking to Arnav, I plan to spend some
> > time
> > > on
> > > > > the
> > > > > > ALP implementation in the arrow-go repository helping spread the
> > > > support
> > > > > to
> > > > > > more languages.
> > > > > >
> > > > > > Best
> > > > > > Prateek
> > > > > >
> > > > > > On Sun, Aug 2, 2026 at 10:42 PM PRATEEK GAUR <prtkgaur@gmail.com
> >
> > > > wrote:
> > > > > >
> > > > > > > Thanks Divjot for bringing it up.
> > > > > > >
> > > > > > > I was under the same impression as Russell and Andrew that we'd
> > > have
> > > > it
> > > > > > > flag gated.
> > > > > > > With the new versioning proposal 'preview' might be a good tag
> > for
> > > > it.
> > > > > > >
> > > > > > > Best
> > > > > > > Prateek
> > > > > > >
> > > > > > > On Sat, Aug 1, 2026 at 12:39 AM Andrew Lamb <
> > > andrewlamb11@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > >> Div: Here is a proposal to mark ALP in Preview: [1] (using a
> > > comment
> > > > > in
> > > > > > >> the
> > > > > > >> spec section).
> > > > > > >>
> > > > > > >> Russel: That is my understanding as well.
> > > > > > >>
> > > > > > >> Hopefully we are able to formalize the versioning process
> > shortly
> > > so
> > > > > we
> > > > > > >> can
> > > > > > >> formalize the notion of "preview"
> > > > > > >>
> > > > > > >> Andrew
> > > > > > >>
> > > > > > >>
> > > > > > >> [1]: https://github.com/apache/parquet-format/pull/604
> > > > > > >>
> > > > > > >> On Fri, Jul 31, 2026 at 11:15 AM Russell Spitzer <
> > > > > > >> russell.spitzer@gmail.com>
> > > > > > >> wrote:
> > > > > > >>
> > > > > > >> > I thought we had agreed it would be merged, and features
> like
> > > this
> > > > > > would
> > > > > > >> > be feature flag gated. So a V-Old writer could always opt in
> > to
> > > > > using
> > > > > > >> this
> > > > > > >> > encoding but that must be a conscious effort if you are not
> > > using
> > > > > > VNext
> > > > > > >> of
> > > > > > >> > Parquet. If you are on V-Next the writer can choose to use
> ALP
> > > > > > whenever
> > > > > > >> it
> > > > > > >> > likes without user intervention.
> > > > > > >> >
> > > > > > >> > On Fri, Jul 31, 2026 at 2:20 AM Divjot Arora via dev <
> > > > > > >> > dev@parquet.apache.org> wrote:
> > > > > > >> >
> > > > > > >> >> Yes, that’s my understanding as well. However, as you
> noted,
> > > the
> > > > > > >> >> versioning
> > > > > > >> >> discussion is still in early stages and hasn’t prescribed
> > > > concrete
> > > > > > >> >> mechanisms yet. If ALP goes into parquet-format 2.14.0,
> > there’s
> > > > no
> > > > > > >> >> indication that it’s in preview or that writers shouldn’t
> use
> > > it
> > > > by
> > > > > > >> >> default
> > > > > > >> >> yet. Given that we’ve held off on merging other
> incompatible
> > > > > changes
> > > > > > >> (e.g
> > > > > > >> >> removal of path_in_schema) until the versioning discussion
> > > > closes,
> > > > > my
> > > > > > >> >> preference would be to leave ALP un-merged for the time
> being
> > > as
> > > > > > well.
> > > > > > >> >>
> > > > > > >> >> — Div
> > > > > > >> >>
> > > > > > >> >> On Fri, Jul 31, 2026 at 08:59 Andrew Lamb <
> > > > andrewlamb11@gmail.com>
> > > > > > >> wrote:
> > > > > > >> >>
> > > > > > >> >> > After re-reading Julien's Versioning Proposal, my
> > > understanding
> > > > > is
> > > > > > >> that
> > > > > > >> >> if
> > > > > > >> >> > we adopt that system, we will somehow mark ALP in
> "Preview"
> > > in
> > > > > > >> >> > parquet-format for release Version 3.
> > > > > > >> >> >
> > > > > > >> >> > The versioning document doesn't seem to proscribe the
> > > > particular
> > > > > > >> method
> > > > > > >> >> > for annotating "preview" features -- I think clearly
> > marking
> > > > them
> > > > > > as
> > > > > > >> >> such
> > > > > > >> >> > in parquet.thrift as well as reflecting that on the
> > > > > > >> >> > https://parquet.apache.org/docs/file-format/versions/
> page
> > > > > somehow
> > > > > > >> >> would
> > > > > > >> >> > be adequate.
> > > > > > >> >> >
> > > > > > >> >> > Andrew
> > > > > > >> >> >
> > > > > > >> >> > On Thu, Jul 30, 2026 at 11:50 AM Andrew Lamb <
> > > > > > andrewlamb11@gmail.com
> > > > > > >> >
> > > > > > >> >> > wrote:
> > > > > > >> >> >
> > > > > > >> >> >> In my mind ALP is in the same position as other
> encodings
> > > that
> > > > > > were
> > > > > > >> >> added
> > > > > > >> >> >> recently[1] (such as BYTE_STREAM_SPLIT for non floating
> > > point
> > > > > > types)
> > > > > > >> >> >>
> > > > > > >> >> >> That is to say it will be available in the latest open
> > > source
> > > > > > >> writers
> > > > > > >> >> and
> > > > > > >> >> >> readers, but realistically not widely used in the
> > ecosystem
> > > > > where
> > > > > > >> >> >> compatibility is a concern (a large part)
> > > > > > >> >> >>
> > > > > > >> >> >> I view Julian's work[2][3] to gather consensus on how to
> > > name
> > > > > > >> >> >> combinations of features (e.g. "versions") as the
> > mechanism
> > > by
> > > > > > >> which we
> > > > > > >> >> >> will accelerate the adoption of this change (along with
> > > other
> > > > > > >> forward
> > > > > > >> >> >> incompatible changes) across the ecosystem.
> > > > > > >> >> >>
> > > > > > >> >> >> > Will we exclude this change when cutting
> parquet-format
> > > > > v2.14.0?
> > > > > > >> >> >>
> > > > > > >> >> >> No I don't think so -- I would expect it to go out in
> the
> > > next
> > > > > > >> >> >> parquet-format version as do other changes in the spec.
> > > > > > >> >> >>
> > > > > > >> >> >> Andrew
> > > > > > >> >> >>
> > > > > > >> >> >> [1]:
> > https://parquet.apache.org/docs/file-format/versions/
> > > > > > >> >> >> [2]:
> > > > > > >>
> > https://lists.apache.org/thread/xmnj8h0h8ozmrgox5tydhhs7yz7q2hss
> > > > > > >> >> >> [3]:
> > > > > > >>
> > https://lists.apache.org/thread/qlf8lg90gqq41lllyy9mk2f0skqvftqj
> > > > > > >> >> >>
> > > > > > >> >> >>
> > > > > > >> >> >> On Thu, Jul 30, 2026 at 3:51 AM Divjot Arora via dev <
> > > > > > >> >> >> dev@parquet.apache.org> wrote:
> > > > > > >> >> >>
> > > > > > >> >> >>> Hi Andrew,
> > > > > > >> >> >>>
> > > > > > >> >> >>> How does this interact with the ongoing versioning
> > > > discussion?
> > > > > > >> Given
> > > > > > >> >> that
> > > > > > >> >> >>> new encodings are not forward compatible, I would
> assume
> > > ALP
> > > > is
> > > > > > >> >> included
> > > > > > >> >> >>> in
> > > > > > >> >> >>> Parquet V<next> (V3?), but it's not clear to me how
> that
> > > > works
> > > > > if
> > > > > > >> it's
> > > > > > >> >> >>> merged to the parquet-format master branch now. Will we
> > > > exclude
> > > > > > >> this
> > > > > > >> >> >>> change
> > > > > > >> >> >>> when cutting parquet-format v2.14.0?
> > > > > > >> >> >>>
> > > > > > >> >> >>> -- Div
> > > > > > >> >> >>>
> > > > > > >> >> >>> On Thu, Jul 30, 2026 at 8:51 AM Andrew Lamb <
> > > > > > >> andrewlamb11@gmail.com>
> > > > > > >> >> >>> wrote:
> > > > > > >> >> >>>
> > > > > > >> >> >>> > Hello,
> > > > > > >> >> >>> >
> > > > > > >> >> >>> > As an update, thanks to the epic work from many
> > > > contributors,
> > > > > > >> >> >>> especially
> > > > > > >> >> >>> > Prateek, I just merged the parquet-format change for
> > > > ALP[1].
> > > > > We
> > > > > > >> >> plan to
> > > > > > >> >> >>> > make additional editorial The remaining items I know
> of
> > > are
> > > > > > >> merging
> > > > > > >> >> the
> > > > > > >> >> >>> > examples from parquet-testing[2], and then of course
> > the
> > > > > > various
> > > > > > >> >> >>> > implementations
> > > > > > >> >> >>> >
> > > > > > >> >> >>> > Thanks again everyone. This is a great step forward
> > > > > > >> >> >>> > Andrew
> > > > > > >> >> >>> >
> > > > > > >> >> >>> > [1]:
> https://github.com/apache/parquet-format/pull/557
> > > > > > >> >> >>> > [2]:
> > https://github.com/apache/parquet-testing/pull/100
> > > > > > >> >> >>> >
> > > > > > >> >> >>> > On Tue, Jul 21, 2026 at 4:39 PM Julien Le Dem <
> > > > > > julien@apache.org
> > > > > > >> >
> > > > > > >> >> >>> wrote:
> > > > > > >> >> >>> >
> > > > > > >> >> >>> > > It was also in my spam folder... :(
> > > > > > >> >> >>> > > I've seen a bunch of apache list emails go to my
> spam
> > > > > > recently.
> > > > > > >> >> >>> > >
> > > > > > >> >> >>> > > On Tue, Jul 21, 2026 at 10:58 AM Russell Spitzer <
> > > > > > >> >> >>> > > russell.spitzer@gmail.com>
> > > > > > >> >> >>> > > wrote:
> > > > > > >> >> >>> > >
> > > > > > >> >> >>> > > > Yes, my hope was that my vote would kick it out
> of
> > > spam
> > > > > but
> > > > > > >> we
> > > > > > >> >> >>> > definitely
> > > > > > >> >> >>> > > > had two other votes that also went to spam for
> me.
> > > > > > >> >> >>> > > >
> > > > > > >> >> >>> > > > For anyone looking the thread is here
> > > > > > >> >> >>> > > >
> > > > > > >> >>
> > > https://lists.apache.org/thread/hgmd58wrv9yoopcrf61m1bg211l65tbt
> > > > > > >> >> >>> > > >
> > > > > > >> >> >>> > > > On Tue, Jul 21, 2026 at 10:57 AM Micah Kornfield
> <
> > > > > > >> >> >>> > emkornfield@gmail.com>
> > > > > > >> >> >>> > > > wrote:
> > > > > > >> >> >>> > > >
> > > > > > >> >> >>> > > > > I've seen other's votes not go to spam, so
> > > hopefully
> > > > > > people
> > > > > > >> >> will
> > > > > > >> >> >>> see
> > > > > > >> >> >>> > it
> > > > > > >> >> >>> > > > in
> > > > > > >> >> >>> > > > > there inboxes (or see this thread and look in
> > there
> > > > > > spam).
> > > > > > >> >> >>> > > > >
> > > > > > >> >> >>> > > > > On Tue, Jul 21, 2026 at 10:52 AM PRATEEK GAUR <
> > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > wrote:
> > > > > > >> >> >>> > > > >
> > > > > > >> >> >>> > > > > > Okay,
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > > > I sent out the voting email yesterday and so
> > far
> > > > I've
> > > > > > >> heard
> > > > > > >> >> >>> from 3
> > > > > > >> >> >>> > > > people
> > > > > > >> >> >>> > > > > > that it ended up in their "spam folder". Dev
> > VPN
> > > to
> > > > > be
> > > > > > >> >> blamed
> > > > > > >> >> >>> for
> > > > > > >> >> >>> > > it?.
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > > > What's the protocol here?
> > > > > > >> >> >>> > > > > > I let people hunt for the email in their spam
> > > > folder
> > > > > or
> > > > > > >> send
> > > > > > >> >> >>> out
> > > > > > >> >> >>> > > > another
> > > > > > >> >> >>> > > > > > one?
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > > > Best
> > > > > > >> >> >>> > > > > > Prateek
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > > > On Sun, Jul 19, 2026 at 10:47 PM PRATEEK
> GAUR <
> > > > > > >> >> >>> prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > > wrote:
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > > > > Hi team,
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > Vinoo has added the tests which were
> > requested
> > > in
> > > > > the
> > > > > > >> last
> > > > > > >> >> >>> round
> > > > > > >> >> >>> > of
> > > > > > >> >> >>> > > > > > review.
> > > > > > >> >> >>> > > > > > > In his own words.
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > "
> > > > > > >> >> >>> > > > > > > The extreme value tests Micah wanted are
> done
> > > and
> > > > > > >> pushed.
> > > > > > >> >> I
> > > > > > >> >> >>> added
> > > > > > >> >> >>> > > > > > coverage
> > > > > > >> >> >>> > > > > > > for values that need the full FOR bit width
> > > after
> > > > > the
> > > > > > >> >> frame
> > > > > > >> >> >>> of
> > > > > > >> >> >>> > > > > reference
> > > > > > >> >> >>> > > > > > is
> > > > > > >> >> >>> > > > > > > applied: 64-bit (the case where the signed
> > max
> > > > > minus
> > > > > > >> min
> > > > > > >> >> >>> > > subtraction
> > > > > > >> >> >>> > > > > > > overflows), 63-bit (the non-overflow case),
> > and
> > > > > > 32-bit
> > > > > > >> for
> > > > > > >> >> >>> > floats.
> > > > > > >> >> >>> > > > All
> > > > > > >> >> >>> > > > > > > lossless with zero exceptions. I also
> > verified
> > > > them
> > > > > > >> >> through
> > > > > > >> >> >>> Arrow
> > > > > > >> >> >>> > > C++
> > > > > > >> >> >>> > > > > ALP
> > > > > > >> >> >>> > > > > > > reader (the local build), so the
> Java-written
> > > > > extreme
> > > > > > >> >> columns
> > > > > > >> >> >>> > > decode
> > > > > > >> >> >>> > > > > > > correctly in C++, bit-exact against the
> > > expected
> > > > > > >> values."
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > State of the PR (#3397):
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > >    - Merges cleanly with master (I pulled
> > > master
> > > > in
> > > > > > and
> > > > > > >> >> >>> resolved
> > > > > > >> >> >>> > > the
> > > > > > >> >> >>> > > > > > >    conflicts).
> > > > > > >> >> >>> > > > > > >    - 41 of 44 review threads resolved. The
> 3
> > > > > > remaining
> > > > > > >> are
> > > > > > >> >> >>> > > > intentional:
> > > > > > >> >> >>> > > > > > >    one deferred perf nit, one that stays
> open
> > > > until
> > > > > > >> >> >>> > parquet-format
> > > > > > >> >> >>> > > > > ships
> > > > > > >> >> >>> > > > > > ALP,
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > "
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > With this both the
> > > > > > >> >> >>> > > > > > > 1) C++ PR :
> > > > > > >> >> >>> https://github.com/apache/arrow/pull/48345/changes
> > > > > > >> >> >>> > > > > > > 2) Java PR :
> > > > > > >> >> >>> https://github.com/apache/parquet-java/pull/3397
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > Are cross language tested and range of test
> > > > > > scenarios.
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > Best
> > > > > > >> >> >>> > > > > > > Prateek
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > > On Mon, Jul 13, 2026 at 8:38 AM PRATEEK
> GAUR
> > <
> > > > > > >> >> >>> prtkgaur@gmail.com
> > > > > > >> >> >>> > >
> > > > > > >> >> >>> > > > > wrote:
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > >> Thanks Matt,
> > > > > > >> >> >>> > > > > > >>
> > > > > > >> >> >>> > > > > > >> I'll be on it this week.
> > > > > > >> >> >>> > > > > > >>
> > > > > > >> >> >>> > > > > > >> Best
> > > > > > >> >> >>> > > > > > >> Prateek
> > > > > > >> >> >>> > > > > > >>
> > > > > > >> >> >>> > > > > > >> On Mon, Jul 13, 2026 at 8:36 AM Matt
> Topol <
> > > > > > >> >> >>> > > zotthewizard@gmail.com>
> > > > > > >> >> >>> > > > > > >> wrote:
> > > > > > >> >> >>> > > > > > >>
> > > > > > >> >> >>> > > > > > >>> There is also the Go implementation
> > submitted
> > > > by
> > > > > > >> Arnav (
> > > > > > >> >> >>> > > > > > >>>
> > https://github.com/apache/arrow-go/pull/704)
> > > > > which
> > > > > > >> is
> > > > > > >> >> >>> waiting
> > > > > > >> >> >>> > > for
> > > > > > >> >> >>> > > > > > >>> updates.
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>> > > > > > >>> Just wanted to make sure it didn't get
> lost
> > > > here.
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>> > > > > > >>> --Matt
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>> > > > > > >>> On Mon, Jul 13, 2026 at 11:30 AM PRATEEK
> > > GAUR <
> > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>> > > > > > >>> > Hi all,
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > I'd like to share a status update on
> the
> > > ALP
> > > > > > >> encoding
> > > > > > >> >> >>> effort
> > > > > > >> >> >>> > > and
> > > > > > >> >> >>> > > > > get
> > > > > > >> >> >>> > > > > > a
> > > > > > >> >> >>> > > > > > >>> feel
> > > > > > >> >> >>> > > > > > >>> > from the community before starting a
> > formal
> > > > > vote.
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > We now have the specification plus
> > > > > > implementations
> > > > > > >> in
> > > > > > >> >> >>> both
> > > > > > >> >> >>> > > > > languages:
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> >     - Spec:
> > > >  apache/parquet-format#557 —
> > > > > > >> GH-533
> > > > > > >> >> >>> Add
> > > > > > >> >> >>> > ALP
> > > > > > >> >> >>> > > > > > encoding
> > > > > > >> >> >>> > > > > > >>> > specification
> > > > > > >> >> >>> > > > > > >>> >     - C++ (Arrow):  apache/arrow#48345
> —
> > > > > GH-48701
> > > > > > >> >> >>> > > [C++][Parquet]
> > > > > > >> >> >>> > > > > Add
> > > > > > >> >> >>> > > > > > >>> ALPpd
> > > > > > >> >> >>> > > > > > >>> > encoding
> > > > > > >> >> >>> > > > > > >>> >     - Java:
> > >  apache/parquet-java#3397
> > > > —
> > > > > > >> Parquet
> > > > > > >> >> >>> Java
> > > > > > >> >> >>> > ALP
> > > > > > >> >> >>> > > > > > >>> > Implementation (by Vinoo)
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > Current state:
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> >     - The C++ implementation has been
> > > through
> > > > > 3-4
> > > > > > >> >> rounds
> > > > > > >> >> >>> of
> > > > > > >> >> >>> > > > review.
> > > > > > >> >> >>> > > > > > >>> >     - The Java implementation has been
> > > > tracking
> > > > > > >> well
> > > > > > >> >> and
> > > > > > >> >> >>> has
> > > > > > >> >> >>> > > had
> > > > > > >> >> >>> > > > > > >>> initial
> > > > > > >> >> >>> > > > > > >>> >       reviews from contributors, with
> no
> > > > major
> > > > > > >> >> remaining
> > > > > > >> >> >>> > > issues.
> > > > > > >> >> >>> > > > > > >>> >     - Cross-language compatibility
> tests
> > > are
> > > > > > >> passing:
> > > > > > >> >> the
> > > > > > >> >> >>> > Arrow
> > > > > > >> >> >>> > > > C++
> > > > > > >> >> >>> > > > > > >>> decoder
> > > > > > >> >> >>> > > > > > >>> >       reads Java-written data
> bit-exactly
> > > > > across
> > > > > > >> >> ~1.56M
> > > > > > >> >> >>> > values
> > > > > > >> >> >>> > > > and
> > > > > > >> >> >>> > > > > 18
> > > > > > >> >> >>> > > > > > >>> >       fixtures, covering V1 and V2
> pages,
> > > > > > multiple
> > > > > > >> >> vector
> > > > > > >> >> >>> > > sizes,
> > > > > > >> >> >>> > > > > and
> > > > > > >> >> >>> > > > > > >>> > several
> > > > > > >> >> >>> > > > > > >>> >       real datasets — zero mismatches.
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> >  As raised in the java-pr we will be
> > adding
> > > > > > >> coverage
> > > > > > >> >> for
> > > > > > >> >> >>> > > extreme
> > > > > > >> >> >>> > > > > > values
> > > > > > >> >> >>> > > > > > >>> > (those requiring
> > > > > > >> >> >>> > > > > > >>> >  63-64 bits after FOR is applied)
> before
> > we
> > > > > > close a
> > > > > > >> >> vote.
> > > > > > >> >> >>> > We'll
> > > > > > >> >> >>> > > > aim
> > > > > > >> >> >>> > > > > > to
> > > > > > >> >> >>> > > > > > >>> get
> > > > > > >> >> >>> > > > > > >>> > that
> > > > > > >> >> >>> > > > > > >>> >  done in parallel.
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > Plan: unless there are objections, I
> > intend
> > > > to
> > > > > > >> start a
> > > > > > >> >> >>> vote
> > > > > > >> >> >>> > at
> > > > > > >> >> >>> > > > the
> > > > > > >> >> >>> > > > > > end
> > > > > > >> >> >>> > > > > > >>> of
> > > > > > >> >> >>> > > > > > >>> > this week/early
> > > > > > >> >> >>> > > > > > >>> > next week.
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > Thanks
> > > > > > >> >> >>> > > > > > >>> > Prateek
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > On Wed, Jul 1, 2026 at 8:50 AM PRATEEK
> > > GAUR <
> > > > > > >> >> >>> > > prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > > > >>> wrote:
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>> > > Hi Team,
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> > > Just wanted to provide some updates
> on
> > > ALP.
> > > > > > >> >> >>> > > > > > >>> > > Micah and I have done 3-4 rounds of
> > > review
> > > > > for
> > > > > > >> the
> > > > > > >> >> c++
> > > > > > >> >> >>> PR :
> > > > > > >> >> >>> > > > > > >>> > >
> > > https://github.com/apache/arrow/pull/48345
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> > > For the Java implementation Vinoo has
> > > been
> > > > > > >> working
> > > > > > >> >> on
> > > > > > >> >> >>> > > following
> > > > > > >> >> >>> > > > > PR
> > > > > > >> >> >>> > > > > > :
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > https://github.com/apache/parquet-java/pull/3397
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> > > Best
> > > > > > >> >> >>> > > > > > >>> > > Prateek
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> > > On Tue, May 5, 2026 at 1:50 PM Micah
> > > > > Kornfield
> > > > > > <
> > > > > > >> >> >>> > > > > > >>> emkornfield@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > > wrote:
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> > >> Hi Antoine,
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> > already
> > > > > asked,
> > > > > > >> but
> > > > > > >> >> >>> should
> > > > > > >> >> >>> > we
> > > > > > >> >> >>> > > > > care
> > > > > > >> >> >>> > > > > > >>> about
> > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT + ALP
> be
> > > more
> > > > > > >> >> efficient
> > > > > > >> >> >>> than
> > > > > > >> >> >>> > > > > FLOAT16
> > > > > > >> >> >>> > > > > > +
> > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> example?
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >> It was.  We thought we could defer
> it
> > > for
> > > > > the
> > > > > > >> >> >>> following
> > > > > > >> >> >>> > > > reasons:
> > > > > > >> >> >>> > > > > > >>> > >> 1.  It's not clear there are a lot
> of
> > > easy
> > > > > > >> >> reference
> > > > > > >> >> >>> > > datasets
> > > > > > >> >> >>> > > > to
> > > > > > >> >> >>> > > > > > >>> test
> > > > > > >> >> >>> > > > > > >>> > its
> > > > > > >> >> >>> > > > > > >>> > >> effectiveness.  It does look like
> > there
> > > > > might
> > > > > > be
> > > > > > >> >> one
> > > > > > >> >> >>> or
> > > > > > >> >> >>> > two
> > > > > > >> >> >>> > > on
> > > > > > >> >> >>> > > > > > >>> > huggingface
> > > > > > >> >> >>> > > > > > >>> > >> (e.g.
> > > > > > >> >> https://huggingface.co/datasets/kikitora/curdie
> > > > > > >> >> >>> ).
> > > > > > >> >> >>> > > > > > >>> > >> 2.  It seemed likely that float 16
> was
> > > > more
> > > > > > >> likely
> > > > > > >> >> >>> used
> > > > > > >> >> >>> > for
> > > > > > >> >> >>> > > > > values
> > > > > > >> >> >>> > > > > > >>> that
> > > > > > >> >> >>> > > > > > >>> > >> were less likely to reduce to
> decimal
> > > > > values.
> > > > > > >> >> >>> > > > > > >>> > >> 3.  It could be added as an
> extension
> > > > later
> > > > > if
> > > > > > >> >> needed.
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >> Cheers,
> > > > > > >> >> >>> > > > > > >>> > >> Micah
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >> On Tue, May 5, 2026 at 1:40 PM
> Antoine
> > > > > Pitrou
> > > > > > <
> > > > > > >> >> >>> > > > > antoine@python.org
> > > > > > >> >> >>> > > > > > >
> > > > > > >> >> >>> > > > > > >>> > wrote:
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > Hello,
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > Apologies if the question was
> > already
> > > > > asked,
> > > > > > >> but
> > > > > > >> >> >>> should
> > > > > > >> >> >>> > we
> > > > > > >> >> >>> > > > > care
> > > > > > >> >> >>> > > > > > >>> about
> > > > > > >> >> >>> > > > > > >>> > >> > FLOAT16 for ALP? Can FLOAT + ALP
> be
> > > more
> > > > > > >> >> efficient
> > > > > > >> >> >>> than
> > > > > > >> >> >>> > > > > FLOAT16
> > > > > > >> >> >>> > > > > > +
> > > > > > >> >> >>> > > > > > >>> > >> > BYTE_STREAM_SPLIT + LZ4 for
> example?
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > Regards
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > Antoine.
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > Le 30/04/2026 à 01:10, PRATEEK
> GAUR
> > a
> > > > > écrit
> > > > > > :
> > > > > > >> >> >>> > > > > > >>> > >> > > Thanks Andrew and Micah for
> review
> > > > > > feedback
> > > > > > >> on
> > > > > > >> >> >>> the two
> > > > > > >> >> >>> > > > PR's
> > > > > > >> >> >>> > > > > > >>> > >> > > 1) (c++ arrow repo)
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> https://github.com/apache/arrow/pull/48345/changes
> > > > > > >> >> >>> > > > > > >>> > >> > > 2) (parquet-format repo)
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> https://github.com/apache/parquet-format/pull/557
> > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > >> >> >>> > > > > > >>> > >> > > I have addressed all (unless I
> > > missed
> > > > > > >> >> something)
> > > > > > >> >> >>> > > comments
> > > > > > >> >> >>> > > > on
> > > > > > >> >> >>> > > > > > >>> the two
> > > > > > >> >> >>> > > > > > >>> > >> > PR's.
> > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > >> >> >>> > > > > > >>> > >> > > Best
> > > > > > >> >> >>> > > > > > >>> > >> > > Prateek
> > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > >> >> >>> > > > > > >>> > >> > > On Sat, Apr 25, 2026 at 1:08 PM
> > > > PRATEEK
> > > > > > >> GAUR <
> > > > > > >> >> >>> > > > > > >>> prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > >> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > >> >> >>> > > > > > >>> > >> > >> Thanks Andrew and Micah.
> > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > >> >> >>> > > > > > >>> > >> > >> `fair amount of feedback on at
> > > least
> > > > > the
> > > > > > >> >> >>> > > implementations`
> > > > > > >> >> >>> > > > > > >>> > >> > >> For the c++ I have already
> > started
> > > > > > >> addressing
> > > > > > >> >> the
> > > > > > >> >> >>> > > > > feedback, I
> > > > > > >> >> >>> > > > > > >>> > should
> > > > > > >> >> >>> > > > > > >>> > >> be
> > > > > > >> >> >>> > > > > > >>> > >> > >> done with that Monday/Tuesday.
> > > > > > >> >> >>> > > > > > >>> > >> > >> I think Vinoo too has been
> making
> > > > good
> > > > > > >> >> progress
> > > > > > >> >> >>> on
> > > > > > >> >> >>> > the
> > > > > > >> >> >>> > > > Java
> > > > > > >> >> >>> > > > > > >>> > >> > implementation.
> > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > >> >> >>> > > > > > >>> > >> > >> Best
> > > > > > >> >> >>> > > > > > >>> > >> > >> Prateek
> > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > >> >> >>> > > > > > >>> > >> > >> On Sat, Apr 25, 2026 at
> 12:55 PM
> > > > Andrew
> > > > > > >> Lamb <
> > > > > > >> >> >>> > > > > > >>> > andrewlamb11@gmail.com
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > >> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>
> > > > > > >> >> >>> > > > > > >>> > >> > >>> Got it. Thank you for the
> > > > > clarification
> > > > > > >> -- I
> > > > > > >> >> >>> will
> > > > > > >> >> >>> > try
> > > > > > >> >> >>> > > > and
> > > > > > >> >> >>> > > > > > look
> > > > > > >> >> >>> > > > > > >>> > into
> > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > >> >> >>> > > > > > >>> > >> > >>> spec and the Rust
> > > implementation[1]
> > > > in
> > > > > > >> this
> > > > > > >> >> next
> > > > > > >> >> >>> > week
> > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>> [1]:
> > > > > > >> >> >>> https://github.com/apache/arrow-rs/pull/9372
> > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>> On Sat, Apr 25, 2026 at
> 12:01 PM
> > > > Micah
> > > > > > >> >> >>> Kornfield <
> > > > > > >> >> >>> > > > > > >>> > >> > emkornfield@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > >> > >>> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>> Hi Andrew,
> > > > > > >> >> >>> > > > > > >>> > >> > >>>> I think there is a fair
> amount
> > of
> > > > > > >> feedback
> > > > > > >> >> on
> > > > > > >> >> >>> at
> > > > > > >> >> >>> > > least
> > > > > > >> >> >>> > > > > the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>> implementations, typically I
> > > think
> > > > > > we've
> > > > > > >> >> waited
> > > > > > >> >> >>> > till
> > > > > > >> >> >>> > > > they
> > > > > > >> >> >>> > > > > > are
> > > > > > >> >> >>> > > > > > >>> > >> close to
> > > > > > >> >> >>> > > > > > >>> > >> > >>>> mergeable before a final
> vote.
> > > > > > >> Otherwise I
> > > > > > >> >> >>> agree
> > > > > > >> >> >>> > we
> > > > > > >> >> >>> > > > are
> > > > > > >> >> >>> > > > > > very
> > > > > > >> >> >>> > > > > > >>> > >> close.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>> -Micah
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>> On Saturday, April 25, 2026,
> > > Andrew
> > > > > > Lamb
> > > > > > >> <
> > > > > > >> >> >>> > > > > > >>> andrewlamb11@gmail.com
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> > >> > wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Thanks Prateek,
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> I think from this content it
> > > looks
> > > > > to
> > > > > > me
> > > > > > >> >> like
> > > > > > >> >> >>> we
> > > > > > >> >> >>> > are
> > > > > > >> >> >>> > > > > ready
> > > > > > >> >> >>> > > > > > >>> to
> > > > > > >> >> >>> > > > > > >>> > >> start a
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> vote to explicitly accept
> ALP
> > > into
> > > > > > >> Parquet
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Does anyone know of a reason
> > we
> > > > > should
> > > > > > >> >> >>> postpone it
> > > > > > >> >> >>> > > for
> > > > > > >> >> >>> > > > > > >>> longer?
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Perhaps someone needs some
> > more
> > > > time
> > > > > > to
> > > > > > >> >> >>> review?
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> Andrew
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> On Wed, Apr 22, 2026 at
> > 1:00 PM
> > > > > > PRATEEK
> > > > > > >> >> GAUR <
> > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hi team,
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Hope everyone is doing
> well.
> > I
> > > > got
> > > > > a
> > > > > > >> >> chance
> > > > > > >> >> >>> to
> > > > > > >> >> >>> > work
> > > > > > >> >> >>> > > > > > >>> through all
> > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> remaining feedback and
> update
> > > the
> > > > > > spec
> > > > > > >> >> doc.
> > > > > > >> >> >>> Here
> > > > > > >> >> >>> > > are
> > > > > > >> >> >>> > > > > the
> > > > > > >> >> >>> > > > > > >>> new
> > > > > > >> >> >>> > > > > > >>> > >> > artifacts
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 1) Spec document :
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > >
> > > > > > >> >> >>> > > >
> > > > > > >> >> >>> > >
> > > > > > >> >> >>> >
> > > > > > >> >> >>>
> > > > > > >> >>
> > > > > > >>
> > > > > >
> > > > >
> > > >
> > >
> >
> https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-3fPtD_aWt/edit
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 2) Spec document in parquet
> > > > format
> > > > > > >> repo :
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > https://github.com/apache/parquet-format/pull/557
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 3) Alp implementation in
> > arrow
> > > > c++
> > > > > > >> repo :
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > https://github.com/apache/arrow/pull/48345/changes
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 4) Alp implementation in
> > > > > parquet-java
> > > > > > >> >> repo :
> > > > > > >> >> >>> Work
> > > > > > >> >> >>> > > for
> > > > > > >> >> >>> > > > > > >>> Vinoo and
> > > > > > >> >> >>> > > > > > >>> > >> > Julien
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > https://github.com/apache/parquet-java/pull/3397
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> 5) PR with test and
> > > benchmarking
> > > > > > >> >> artifacts in
> > > > > > >> >> >>> > > > > > >>> parquet-testing
> > > > > > >> >> >>> > > > > > >>> > >> repo :
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > https://github.com/apache/parquet-testing/pull/100
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> And
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Go : Arnav just
> > submitted
> > > > an
> > > > > in
> > > > > > >> >> >>> progress
> > > > > > >> >> >>> > > > > > >>> implementation
> > > > > > >> >> >>> > > > > > >>> > in
> > > > > > >> >> >>> > > > > > >>> > >> Go.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> https://github.com/apache/arrow-go/pull/704
> > > > > > >> >> >>> > (I
> > > > > > >> >> >>> > > > > > haven't
> > > > > > >> >> >>> > > > > > >>> > >> started
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     looking at it yet)
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     - Rust : I remember
> > Andrew
> > > > > > >> mentioned
> > > > > > >> >> that
> > > > > > >> >> >>> > this
> > > > > > >> >> >>> > > > work
> > > > > > >> >> >>> > > > > > is
> > > > > > >> >> >>> > > > > > >>> also
> > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     progress (So 4
> > languages!)
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Arrow C++ implementation *
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> The PR is out and was also
> > used
> > > > by
> > > > > > >> >> Antoine to
> > > > > > >> >> >>> > > report
> > > > > > >> >> >>> > > > > the
> > > > > > >> >> >>> > > > > > >>> > numbers
> > > > > > >> >> >>> > > > > > >>> > >> as
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> reported here. Micah and
> > > > Konstantin
> > > > > > >> have
> > > > > > >> >> >>> given 1
> > > > > > >> >> >>> > > > round
> > > > > > >> >> >>> > > > > of
> > > > > > >> >> >>> > > > > > >>> > >> feedback
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> and I'm addressing them
> > today.
> > > > > Please
> > > > > > >> note
> > > > > > >> >> >>> that
> > > > > > >> >> >>> > the
> > > > > > >> >> >>> > > > > > default
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> optimization flag for
> > compiling
> > > > is
> > > > > O2
> > > > > > >> and
> > > > > > >> >> not
> > > > > > >> >> >>> > Q3. I
> > > > > > >> >> >>> > > > got
> > > > > > >> >> >>> > > > > > >>> around
> > > > > > >> >> >>> > > > > > >>> > >> 70%
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> performance improvement in
> > the
> > > > > > decoding
> > > > > > >> >> speed
> > > > > > >> >> >>> > when
> > > > > > >> >> >>> > > > > using
> > > > > > >> >> >>> > > > > > >>> the O3
> > > > > > >> >> >>> > > > > > >>> > >> > flag.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> *Parqet-MR Java
> > implementation
> > > > > > (working
> > > > > > >> >> with
> > > > > > >> >> >>> > Vinoo
> > > > > > >> >> >>> > > > and
> > > > > > >> >> >>> > > > > > >>> Julien)
> > > > > > >> >> >>> > > > > > >>> > >> and
> > > > > > >> >> >>> > > > > > >>> > >> > **Cross
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Language testing*
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>     Let me know if you have
> > any
> > > > > > >> questions
> > > > > > >> >> or
> > > > > > >> >> >>> > > > feedback.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Now pasting some
> performance
> > > > > numbers
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    Table 1: C++ ALP Double
> > > > Decode —
> > > > > > >> >> Spotify
> > > > > > >> >> >>> > Columns
> > > > > > >> >> >>> > > > > > >>> (Graviton
> > > > > > >> >> >>> > > > > > >>> > 3,
> > > > > > >> >> >>> > > > > > >>> > >> ARM
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> Neoverse V1)
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>>
> > > ┌──────────────────┬──────────────┬──────────────┬─────────┐
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ Column           │
> -O2
> > > > (MB/s)
> > > > > > │
> > > > > > >> >> -O3
> > > > > > >> >> >>> > > (MB/s)  │
> > > > > > >> >> >>> > > > > > >>> Speedup │
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>>
> > > ├──────────────────┼──────────────┼──────────────┼─────────┤
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ valence          │
> > >  3,155
> > > > > > │
> > > > > > >> >> >>>  5,523
> > > > > > >> >> >>> > >   │
> > > > > > >> >> >>> > > > > > >>> 1.75x  │
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ danceability     │
> > >  3,233
> > > > > > │
> > > > > > >> >> >>>  5,685
> > > > > > >> >> >>> > >   │
> > > > > > >> >> >>> > > > > > >>> 1.76x  │
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ energy           │
> > >  3,197
> > > > > > │
> > > > > > >> >> >>>  5,652
> > > > > > >> >> >>> > >   │
> > > > > > >> >> >>> > > > > > >>> 1.77x  │
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>    │ loudness         │
> > >  3,186
> > > > > > │
> > > > > > >> >> >>>  5,473
> > > > > > >> >> >>> > >   │
> > > > > > >> >> >>> > > > > > >>> 1.72x  │
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>>
> > > └──────────────────┴──────────────┴──────────────┴─────────┘
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> On Wed, Feb 25, 2026 at
> > 9:49 AM
> > > > > > PRATEEK
> > > > > > >> >> GAUR
> > > > > > >> >> >>> <
> > > > > > >> >> >>> > > > > > >>> > prtkgaur@gmail.com
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Micah Kornfield <
> > > > > > >> emkornfield@gmail.com>
> > > > > > >> >> :
> > > > > > >> >> >>> Got
> > > > > > >> >> >>> > > it.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> @Andrew Lamb <
> > > > > > andrewlamb11@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Do you think it would be
> > good
> > > > to
> > > > > > >> start
> > > > > > >> >> >>> moving
> > > > > > >> >> >>> > the
> > > > > > >> >> >>> > > > > spec
> > > > > > >> >> >>> > > > > > >>> > >> development
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> into
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> markdown format, in
> > > preparation
> > > > > for
> > > > > > >> >> >>> finalizing
> > > > > > >> >> >>> > > it?
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Yes I'll update the
> numbers
> > > for
> > > > > some
> > > > > > >> of
> > > > > > >> >> the
> > > > > > >> >> >>> > > > examples I
> > > > > > >> >> >>> > > > > > >>> have in
> > > > > > >> >> >>> > > > > > >>> > >> the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> spec based
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> on the updated header
> size.
> > > Then
> > > > > we
> > > > > > >> >> should
> > > > > > >> >> >>> be
> > > > > > >> >> >>> > good
> > > > > > >> >> >>> > > > to
> > > > > > >> >> >>> > > > > go
> > > > > > >> >> >>> > > > > > >>> for
> > > > > > >> >> >>> > > > > > >>> > the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> markdown format.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>> Thanks everyone!
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Andrew
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> On Tue, Feb 17, 2026 at
> > > 7:28 PM
> > > > > > >> PRATEEK
> > > > > > >> >> >>> GAUR <
> > > > > > >> >> >>> > > > > > >>> > >> prtkgaur@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Hi team,
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 1) Andrew
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for working
> > on
> > > > test
> > > > > > >> files.
> > > > > > >> >> >>> My PR
> > > > > > >> >> >>> > > did
> > > > > > >> >> >>> > > > > add
> > > > > > >> >> >>> > > > > > >>> all
> > > > > > >> >> >>> > > > > > >>> > the
> > > > > > >> >> >>> > > > > > >>> > >> > test
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> files I
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     used to benchmark on
> > > > > datasets.
> > > > > > >> >> Maybe
> > > > > > >> >> >>> we
> > > > > > >> >> >>> > can
> > > > > > >> >> >>> > > > club
> > > > > > >> >> >>> > > > > > it
> > > > > > >> >> >>> > > > > > >>> > >> together.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> WIll also
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> aid
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     cross language
> testing
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     -  Kosta Tarasov
> > working
> > > > on
> > > > > > Rust
> > > > > > >> >> >>> > > > implementation.
> > > > > > >> >> >>> > > > > > >>> This is
> > > > > > >> >> >>> > > > > > >>> > >> > great.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> Thanks
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 2) Antoine
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks a lot for
> > > > reporting
> > > > > > the
> > > > > > >> >> >>> numbers
> > > > > > >> >> >>> > on
> > > > > > >> >> >>> > > > AMD.
> > > > > > >> >> >>> > > > > > >>> Looks
> > > > > > >> >> >>> > > > > > >>> > >> like
> > > > > > >> >> >>> > > > > > >>> > >> > you
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> are
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     getting 8X the
> > decoding
> > > > > > >> >> performance of
> > > > > > >> >> >>> > BSS.
> > > > > > >> >> >>> > > > This
> > > > > > >> >> >>> > > > > > is
> > > > > > >> >> >>> > > > > > >>> > >> > amazing!!.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Thanks for
> > > acknowledging
> > > > > the
> > > > > > >> >> >>> sampling
> > > > > > >> >> >>> > > > design.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - I agree with you
> on
> > > > > > >> Fastlanes. In
> > > > > > >> >> >>> some
> > > > > > >> >> >>> > > crude
> > > > > > >> >> >>> > > > > > >>> > >> experiments I
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> didn't get
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     a good perf benefit
> > from
> > > > it
> > > > > on
> > > > > > >> >> >>> Graviton3
> > > > > > >> >> >>> > > (but
> > > > > > >> >> >>> > > > > > maybe
> > > > > > >> >> >>> > > > > > >>> > there
> > > > > > >> >> >>> > > > > > >>> > >> was
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> something
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     wrong with my
> > > > > implementation).
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Locking the 16bit
> > > > > exception
> > > > > > >> >> >>> encoding for
> > > > > > >> >> >>> > > the
> > > > > > >> >> >>> > > > > > spec
> > > > > > >> >> >>> > > > > > >>> in
> > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> case.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - Awesome I think we
> > > have
> > > > > > solved
> > > > > > >> >> for
> > > > > > >> >> >>> all
> > > > > > >> >> >>> > > open
> > > > > > >> >> >>> > > > > > >>> questions
> > > > > > >> >> >>> > > > > > >>> > >> minus
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     version byte :).
> (will
> > > get
> > > > > > back
> > > > > > >> on
> > > > > > >> >> >>> this
> > > > > > >> >> >>> > > soon)
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> 3) Micah
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     - FastLanes : The
> > > current
> > > > > spec
> > > > > > >> does
> > > > > > >> >> >>> allow
> > > > > > >> >> >>> > > for
> > > > > > >> >> >>> > > > > > using
> > > > > > >> >> >>> > > > > > >>> > >> FastLane
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> with the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     configurable enum
> > value
> > > > for
> > > > > > >> >> layout. We
> > > > > > >> >> >>> > > should
> > > > > > >> >> >>> > > > be
> > > > > > >> >> >>> > > > > > >>> able to
> > > > > > >> >> >>> > > > > > >>> > >> > inject
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> any
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> layout
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>     in the current
> design.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Working on resolving all
> > > > > remaining
> > > > > > >> open
> > > > > > >> >> >>> > comments
> > > > > > >> >> >>> > > > on
> > > > > > >> >> >>> > > > > > the
> > > > > > >> >> >>> > > > > > >>> spec
> > > > > > >> >> >>> > > > > > >>> > >> this
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> week.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Best
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> Prateek
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> On Tue, Feb 10, 2026 at
> > > > 3:37 AM
> > > > > > >> Steve
> > > > > > >> >> >>> > Loughran <
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> stevel@cloudera.com>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> On Sun, 8 Feb 2026 at
> > > 18:12,
> > > > > > Micah
> > > > > > >> >> >>> Kornfield
> > > > > > >> >> >>> > <
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> emkornfield@gmail.com>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> wrote:
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> It looks like the
> actual
> > > > issue
> > > > > > >> >> >>> described for
> > > > > > >> >> >>> > > ORC
> > > > > > >> >> >>> > > > > in
> > > > > > >> >> >>> > > > > > >>> the
> > > > > > >> >> >>> > > > > > >>> > >> paper
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> is that
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> it
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> has multiple
> > sub-encodings
> > > > in
> > > > > a
> > > > > > >> >> batch.
> > > > > > >> >> >>> This
> > > > > > >> >> >>> > > is
> > > > > > >> >> >>> > > > > > >>> different
> > > > > > >> >> >>> > > > > > >>> > >> then
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> the
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>> design
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> proposed here where
> > there
> > > is
> > > > > > still
> > > > > > >> >> fixed
> > > > > > >> >> >>> > > > encoding
> > > > > > >> >> >>> > > > > > per
> > > > > > >> >> >>> > > > > > >>> page
> > > > > > >> >> >>> > > > > > >>> > >> in
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> parquet.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> Given reasonably sized
> > > > pages I
> > > > > > >> don't
> > > > > > >> >> >>> think
> > > > > > >> >> >>> > > > branch
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> misprediction should
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> be a
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> big issue for new
> > > encodings.
> > > > > I
> > > > > > >> agree
> > > > > > >> >> >>> that
> > > > > > >> >> >>> > we
> > > > > > >> >> >>> > > > > should
> > > > > > >> >> >>> > > > > > >>> be
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>> conservative in
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>> general for adding new
> > > > > > encodings.
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>> +1
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >>>>>>>
> > > > > > >> >> >>> > > > > > >>> > >> > >
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >> >
> > > > > > >> >> >>> > > > > > >>> > >>
> > > > > > >> >> >>> > > > > > >>> > >
> > > > > > >> >> >>> > > > > > >>> >
> > > > > > >> >> >>> > > > > > >>>
> > > > > > >> >> >>> > > > > > >>
> > > > > > >> >> >>> > > > > >
> > > > > > >> >> >>> > > > >
> > > > > > >> >> >>> > > >
> > > > > > >> >> >>> > >
> > > > > > >> >> >>> >
> > > > > > >> >> >>>
> > > > > > >> >> >>
> > > > > > >> >>
> > > > > > >> >
> > > > > > >>
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>