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

Peter Smith <smithpb2250@gmail.com>

From: Peter Smith <smithpb2250@gmail.com>
To: Nisha Moond <nisha.moond412@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, shveta malik <shveta.malik@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Amit Kapila <amit.kapila16@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: 2024-12-03T07:00:08Z
Lists: pgsql-hackers

Commits

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  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 Nisha, here are a couple of review comments for patch v52-0001.

======
Commit Message

Add check if slot is already acquired, then mark it invalidate directly.

~

/slot/the slot/

"mark it invalidate" ?

Maybe you meant:
"then invalidate it directly", or
"then mark it 'invalidated' directly", or
etc.

======
src/backend/replication/logical/slotsync.c

1.
@@ -1508,7 +1508,7 @@ ReplSlotSyncWorkerMain(char *startup_data,
size_t startup_data_len)
 static void
 update_synced_slots_inactive_since(void)
 {
- TimestampTz now = 0;
+ TimestampTz now;

  /*
  * We need to update inactive_since only when we are promoting standby to
@@ -1523,6 +1523,9 @@ update_synced_slots_inactive_since(void)
  /* The slot sync worker or SQL function mustn't be running by now */
  Assert((SlotSyncCtx->pid == InvalidPid) && !SlotSyncCtx->syncing);

+ /* Use same inactive_since time for all slots */
+ now = GetCurrentTimestamp();
+

Something is broken with these changes.

AFAICT, the result after applying patch 0001 still has code:
/* Use the same inactive_since time for all the slots. */
if (now == 0)
  now = GetCurrentTimestamp();

So the end result has multiple/competing assignments to variable 'now'.

======
Kind Regards,
Peter Smith.
Fujitsu Australia