Horton

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

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-03-22T13:47:34Z
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 Fri, Mar 22, 2024 at 06:02:11PM +0530, Amit Kapila wrote:
> On Fri, Mar 22, 2024 at 5:30 PM Bertrand Drouvot
> <bertranddrouvot.pg@gmail.com> wrote:
> > On Fri, Mar 22, 2024 at 03:56:23PM +0530, Amit Kapila wrote:
> > > >
> > > > That would avoid testing twice "slot->data.persistency == RS_PERSISTENT".
> > > >
> > >
> > > That sounds like a good idea. Also, don't we need to consider physical
> > > slots where we don't reserve WAL during slot creation? I don't think
> > > there is a need to set inactive_at for such slots.
> >
> > If the slot is not active, why shouldn't we set inactive_at? I can understand
> > that such a slots do not present "any risks" but I think we should still set
> > inactive_at (also to not give the false impression that the slot is active).
> >
> 
> But OTOH, there is a chance that we will invalidate such slots even
> though they have never reserved WAL in the first place which doesn't
> appear to be a good thing.

That's right but I don't think it is not a good thing. I think we should treat
inactive_at as an independent field (like if the timeout one does not exist at
all) and just focus on its meaning (slot being inactive). If one sets a timeout
(> 0) and gets an invalidation then I think it works as designed (even if the
slot does not present any "risk" as it does not hold any rows or WAL). 

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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