Re: Introduce XID age and inactive timeout based replication slot invalidation

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-03-20T08:21:54Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Add a test for commit ac0e33136a using the injection point.

  2. Invalidate inactive replication slots.

  3. Fix incorrect slot type in BuildTupleHashTableExt

  4. Allow synced slots to have their inactive_since.

  5. Change last_inactive_time to inactive_since in pg_replication_slots.

  6. Track last_inactive_time in pg_replication_slots.

  7. Track invalidation_reason in pg_replication_slots.

  8. Add option force_initdb to PostgreSQL::Test::Cluster:init()

  9. Add a failover option to subscriptions.

  10. Allow setting failover property in the replication command.

  11. Allow to enable failover property for replication slots via SQL API.

  12. Track conflict_reason in pg_replication_slots.

  13. Log messages for replication slot acquisition and release.

  14. Remove vacuum_defer_cleanup_age

  15. Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids

  16. meson: Add initial version of meson based build system

Hi,

On Wed, Mar 20, 2024 at 12:48:55AM +0530, Bharath Rupireddy wrote:
> On Mon, Mar 18, 2024 at 3:02 PM Bertrand Drouvot
> <bertranddrouvot.pg@gmail.com> wrote:
> >
> > > > Hm. Are you suggesting inactive_timeout to be a slot level parameter
> > > > similar to 'failover' property added recently by
> > > > c393308b69d229b664391ac583b9e07418d411b6 and
> > > > 73292404370c9900a96e2bebdc7144f7010339cf?
> > >
> > > Yeah, I have something like that in mind. You can prepare the patch
> > > but it would be good if others involved in this thread can also share
> > > their opinion.
> >
> > I think it makes sense to put the inactive_timeout granularity at the slot
> > level (as the activity could vary a lot say between one slot linked to a
> > subcription and one linked to some plugins). As far max_slot_xid_age I've the
> > feeling that a new GUC is good enough.
> 
> Well, here I'm implementing the above idea.

Thanks!

> The attached v12 patches
> majorly have the following changes:
> 
> 2. last_inactive_at and inactive_timeout are now tracked in on-disk
> replication slot data structure.

Should last_inactive_at be tracked on disk? Say the engine is down for a period
of time > inactive_timeout then the slot will be invalidated after the engine
re-start (if no activity before we invalidate the slot). Should the time the
engine is down be counted as "inactive" time? I've the feeling it should not, and
that we should only take into account inactive time while the engine is up.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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