Horton

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

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, shveta malik <shveta.malik@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-04-04T04:34:02Z
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

On Thu, Apr 4, 2024 at 9:42 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> @@ -1368,6 +1416,7 @@ ShutDownSlotSync(void)
>     if (SlotSyncCtx->pid == InvalidPid)
>     {
>         SpinLockRelease(&SlotSyncCtx->mutex);
> +       update_synced_slots_inactive_since();
>         return;
>     }
>     SpinLockRelease(&SlotSyncCtx->mutex);
> @@ -1400,6 +1449,8 @@ ShutDownSlotSync(void)
>     }
>
>     SpinLockRelease(&SlotSyncCtx->mutex);
> +
> +   update_synced_slots_inactive_since();
>  }
>
> Why do we want to update all synced slots' inactive_since values at
> shutdown in spite of updating the value every time when releasing the
> slot? It seems to contradict the fact that inactive_since is updated
> when releasing or restoring the slot.

It is to get the inactive_since right for the cases where the standby
is promoted without a restart similar to when a standby is promoted
with restart in which case the inactive_since is set to current time
in RestoreSlotFromDisk.

Imagine the slot is synced last time at time t1 and then a few hours
passed, the standby is promoted without a restart. If we don't set
inactive_since to current time in this case in ShutDownSlotSync, the
inactive timeout invalidation mechanism can kick in immediately.

-- 
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com