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Posted to dev@cassandra.apache.org by Eric Stevens <mi...@gmail.com> on 2018/06/04 23:02:39 UTC
TWCS - Disabling Tombstone Compactions for TWCS
I'm trying to understand the reasoning behind this stanza in Time Windowed
Compaction Strategy's init:
https://github.com/apache/cassandra/blob/cassandra-3.0.15/src/java/org/apache/cassandra/db/compaction/TimeWindowCompactionStrategy.java#L63-L69
Reposted (and slightly reformatted) here for convenience:
if (
!options.containsKey(AbstractCompactionStrategy.TOMBSTONE_COMPACTION_INTERVAL_OPTION)
&&
!options.containsKey(AbstractCompactionStrategy.TOMBSTONE_THRESHOLD_OPTION)
)
{
disableTombstoneCompactions = true;
logger.debug("Disabling tombstone compactions for TWCS");
}
else
logger.debug("Enabling tombstone compactions for TWCS");
If you have left both tombstone compaction interval, and tombstone
threshold at default values, you are *opting out* of tombstone compactions?
This was certainly a surprising side effect to us, as we expected unset
values to have the same exact effect as setting those values to their
defaults.
I'm wondering if someone can shed some more light on this, or if this
should be considered a bug (it seems really intentional).
Re: TWCS - Disabling Tombstone Compactions for TWCS
Posted by Lerh Chuan Low <le...@instaclustr.com>.
Hi Eric,
Np, I was curious as to why it did that as well. As it turns out, there's
actually a JIRA where it has taken another person by surprise:
https://issues.apache.org/jira/browse/CASSANDRA-14496. You could maybe bump
it too :)
On 7 June 2018 at 03:39, Eric Stevens <mi...@gmail.com> wrote:
> That's helpful background, thanks Lerh! It does seem intentional.
>
> I'd suggest that this violates principal of least surprise (unset defaults
> should have the same effect as setting same to default values), and should
> be worth calling out as a separate option for both DTCS and TWCS.
>
> On Mon, Jun 4, 2018 at 6:02 PM Lerh Chuan Low <le...@instaclustr.com>
> wrote:
>
> > Hi Eric,
> >
> > I think it has something to do with the same reason it is disabled in
> DTCS:
> > https://issues.apache.org/jira/browse/CASSANDRA-9234 can shed more
> light.
> >
> >
> >
> > On 5 June 2018 at 09:02, Eric Stevens <mi...@gmail.com> wrote:
> >
> > > I'm trying to understand the reasoning behind this stanza in Time
> > Windowed
> > > Compaction Strategy's init:
> > > https://github.com/apache/cassandra/blob/cassandra-3.0.
> > > 15/src/java/org/apache/cassandra/db/compaction/
> > > TimeWindowCompactionStrategy.java#L63-L69
> > >
> > > Reposted (and slightly reformatted) here for convenience:
> > > if (
> > >
> > > !options.containsKey(AbstractCompactionStrategy.
> > > TOMBSTONE_COMPACTION_INTERVAL_OPTION)
> > > &&
> > >
> > > !options.containsKey(AbstractCompactionStrategy.
> > > TOMBSTONE_THRESHOLD_OPTION)
> > > )
> > > {
> > > disableTombstoneCompactions = true;
> > > logger.debug("Disabling tombstone compactions for TWCS");
> > > }
> > > else
> > > logger.debug("Enabling tombstone compactions for TWCS");
> > >
> > > If you have left both tombstone compaction interval, and tombstone
> > > threshold at default values, you are *opting out* of tombstone
> > compactions?
> > >
> > > This was certainly a surprising side effect to us, as we expected unset
> > > values to have the same exact effect as setting those values to their
> > > defaults.
> > >
> > > I'm wondering if someone can shed some more light on this, or if this
> > > should be considered a bug (it seems really intentional).
> > >
> >
>
Re: TWCS - Disabling Tombstone Compactions for TWCS
Posted by Eric Stevens <mi...@gmail.com>.
That's helpful background, thanks Lerh! It does seem intentional.
I'd suggest that this violates principal of least surprise (unset defaults
should have the same effect as setting same to default values), and should
be worth calling out as a separate option for both DTCS and TWCS.
On Mon, Jun 4, 2018 at 6:02 PM Lerh Chuan Low <le...@instaclustr.com> wrote:
> Hi Eric,
>
> I think it has something to do with the same reason it is disabled in DTCS:
> https://issues.apache.org/jira/browse/CASSANDRA-9234 can shed more light.
>
>
>
> On 5 June 2018 at 09:02, Eric Stevens <mi...@gmail.com> wrote:
>
> > I'm trying to understand the reasoning behind this stanza in Time
> Windowed
> > Compaction Strategy's init:
> > https://github.com/apache/cassandra/blob/cassandra-3.0.
> > 15/src/java/org/apache/cassandra/db/compaction/
> > TimeWindowCompactionStrategy.java#L63-L69
> >
> > Reposted (and slightly reformatted) here for convenience:
> > if (
> >
> > !options.containsKey(AbstractCompactionStrategy.
> > TOMBSTONE_COMPACTION_INTERVAL_OPTION)
> > &&
> >
> > !options.containsKey(AbstractCompactionStrategy.
> > TOMBSTONE_THRESHOLD_OPTION)
> > )
> > {
> > disableTombstoneCompactions = true;
> > logger.debug("Disabling tombstone compactions for TWCS");
> > }
> > else
> > logger.debug("Enabling tombstone compactions for TWCS");
> >
> > If you have left both tombstone compaction interval, and tombstone
> > threshold at default values, you are *opting out* of tombstone
> compactions?
> >
> > This was certainly a surprising side effect to us, as we expected unset
> > values to have the same exact effect as setting those values to their
> > defaults.
> >
> > I'm wondering if someone can shed some more light on this, or if this
> > should be considered a bug (it seems really intentional).
> >
>
Re: TWCS - Disabling Tombstone Compactions for TWCS
Posted by Lerh Chuan Low <le...@instaclustr.com>.
Hi Eric,
I think it has something to do with the same reason it is disabled in DTCS:
https://issues.apache.org/jira/browse/CASSANDRA-9234 can shed more light.
On 5 June 2018 at 09:02, Eric Stevens <mi...@gmail.com> wrote:
> I'm trying to understand the reasoning behind this stanza in Time Windowed
> Compaction Strategy's init:
> https://github.com/apache/cassandra/blob/cassandra-3.0.
> 15/src/java/org/apache/cassandra/db/compaction/
> TimeWindowCompactionStrategy.java#L63-L69
>
> Reposted (and slightly reformatted) here for convenience:
> if (
>
> !options.containsKey(AbstractCompactionStrategy.
> TOMBSTONE_COMPACTION_INTERVAL_OPTION)
> &&
>
> !options.containsKey(AbstractCompactionStrategy.
> TOMBSTONE_THRESHOLD_OPTION)
> )
> {
> disableTombstoneCompactions = true;
> logger.debug("Disabling tombstone compactions for TWCS");
> }
> else
> logger.debug("Enabling tombstone compactions for TWCS");
>
> If you have left both tombstone compaction interval, and tombstone
> threshold at default values, you are *opting out* of tombstone compactions?
>
> This was certainly a surprising side effect to us, as we expected unset
> values to have the same exact effect as setting those values to their
> defaults.
>
> I'm wondering if someone can shed some more light on this, or if this
> should be considered a bug (it seems really intentional).
>