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

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Peter Smith <smithpb2250@gmail.com>

Cc: Nisha Moond <nisha.moond412@gmail.com>, vignesh C <vignesh21@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, shveta malik <shveta.malik@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2025-02-07T05:52:54Z

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 →

Add a test for commit ac0e33136a using the injection point.
- 8a695d7998be 18.0 landed
Invalidate inactive replication slots.
- ac0e33136abc 18.0 landed
Fix incorrect slot type in BuildTupleHashTableExt
- d96d1d5152f3 18.0 cited
Allow synced slots to have their inactive_since.
- 6f132ed693b6 17.0 landed
Change last_inactive_time to inactive_since in pg_replication_slots.
- 6d49c8d4b4f4 17.0 landed
Track last_inactive_time in pg_replication_slots.
- a11f330b5584 17.0 landed
Track invalidation_reason in pg_replication_slots.
- 6ae701b4378d 17.0 landed
Add option force_initdb to PostgreSQL::Test::Cluster:init()
- ff9e1e764fcc 17.0 cited
Add a failover option to subscriptions.
- 776621a5e479 17.0 cited
Allow setting failover property in the replication command.
- 73292404370c 17.0 cited
Allow to enable failover property for replication slots via SQL API.
- c393308b69d2 17.0 cited
Track conflict_reason in pg_replication_slots.
- 007693f2a3ac 17.0 cited
Log messages for replication slot acquisition and release.
- 7c3fb505b14e 17.0 cited
Remove vacuum_defer_cleanup_age
- 1118cd37eb61 16.0 cited
Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids
- be504a3e974d 16.0 cited
meson: Add initial version of meson based build system
- e6927270cd18 16.0 cited

On Fri, Feb 7, 2025 at 8:00 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> ======
> src/backend/access/transam/xlog.c
>
> 1.
>   XLByteToSeg(RedoRecPtr, _logSegNo, wal_segment_size);
>   KeepLogSeg(recptr, &_logSegNo);
> - if (InvalidateObsoleteReplicationSlots(RS_INVAL_WAL_REMOVED,
> + if (InvalidateObsoleteReplicationSlots(RS_INVAL_WAL_REMOVED |
> RS_INVAL_IDLE_TIMEOUT,
>      _logSegNo, InvalidOid,
>      InvalidTransactionId))
>   {
> @@ -7792,7 +7792,7 @@ CreateRestartPoint(int flags)
>   replayPtr = GetXLogReplayRecPtr(&replayTLI);
>   endptr = (receivePtr < replayPtr) ? replayPtr : receivePtr;
>   KeepLogSeg(endptr, &_logSegNo);
> - if (InvalidateObsoleteReplicationSlots(RS_INVAL_WAL_REMOVED,
> + if (InvalidateObsoleteReplicationSlots(RS_INVAL_WAL_REMOVED |
> RS_INVAL_IDLE_TIMEOUT,
>      _logSegNo, InvalidOid,
>      InvalidTransactionId))
>
> It seems fundamentally strange to me to assign multiple simultaneous
> causes like this. IMO you can't invalidate something that is invalid
> already. I gues v71 was an attempt to implement Amit's:
>

The idea is to invalidate the slot either due to WAL_REMOVED or
IDLE_TIMEOUT in one go during the checkpoint instead of taking
multiple passes over the slots during the checkpoint. Feel free to
suggest if you can think of a better way to implement it.

-- 
With Regards,
Amit Kapila.