Re: Co-processors: Know if row is being deleted by TTL

[Cheyenne Forbes <ch...@gmail.com>]

How do you recommend I implement that feature in hbase?

Regards,

Cheyenne O. Forbes

On Wed, Aug 30, 2017 at 11:57 PM, Anoop John <an...@gmail.com> wrote:

> You cannot rely on postDelete for cells removed because of TTL..
> Because it is not a user started delete op and there wont be any
> postDelete happening for this cell..    The cell is there in some
> HFile.  Even after the TTL time elapsed also..  When a read happens,
> the read flow will filter out such cells from reaching client..  Also
> if there been a compaction happened involving this file,  the cell
> would have got removed.    So you can not really guarantee.
>
> -Anoop-
>
> On Wed, Aug 30, 2017 at 3:15 AM, Ted Yu <yu...@gmail.com> wrote:
> > I wonder if you can make use of per Cell TTL ?
> >
> > See third paragraph under http://hbase.apache.org/book.html#ttl
> >
> > Basically there would be two flags (same row): one for marking whether
> user
> > has submitted the comment, the other is for the TTL you described.
> > When postDelete() is called on the TTL'ed cell, you can retrieve the
> first
> > flag and make decision.
> >
> > FYI
> >
> > On Mon, Aug 28, 2017 at 10:31 PM, Cheyenne Forbes <
> > cheyenne.osanu.forbes@gmail.com> wrote:
> >
> >> I'm sorry, "*postDelete*" wasnt supposed to be a link, I copied the text
> >> and gmail sent it as a link.
> >>
> >> *Use case:*
> >>
> >> When a user is commenting with a photo it is uploaded to be able to be
> >> previewed and the id of the photo is added to a hbase table "tempFiles"
> >> with a 5 hour TTL for each row, if the user submits the comment, the
> row is
> >> deleted manually and *postDelete* would "ignore" it but if it isnt
> >> submitted and the TTL reaches, *postDelete* would run a piece of code
> which
> >> would delete the file from my file server
> >>
> >>
> >> On Mon, Aug 28, 2017 at 5:33 PM, Ted Yu <yu...@gmail.com> wrote:
> >>
> >> > There is no such indication from the book you mentioned.
> >> > Can you tell us your use case where such distinction is needed ?
> >> > -------- Original message --------From: Cheyenne Forbes <
> >> > cheyenne.osanu.forbes@gmail.com> Date: 8/28/17  2:51 PM  (GMT-08:00)
> To:
> >> > user@hbase.apache.org Subject: Co-processors: Know if row is being
> >> > deleted by TTL
> >> > Is is possible to know if a row is being deleted manually or by the
> >> > reaching of the TTL on "*postDelete
> >> > <https://hbase.apache.org/0.94/apidocs/org/apache/hadoop/
> >> > hbase/coprocessor/BaseRegionObserver.html#
> postDelete(org.apache.hadoop.
> >> > hbase.coprocessor.ObserverContext,%20org.apache.
> >> > hadoop.hbase.client.Delete,%20org.apache.hadoop.hbase.
> >> > regionserver.wal.WALEdit,%20boolean)>*
> >> > "?
> >> >
> >> > Regards,
> >> >
> >> > Cheyenne O. Forbes
> >> >
> >>
>