Horton

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

Nisha Moond <nisha.moond412@gmail.com>

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From: Nisha Moond <nisha.moond412@gmail.com>
To: vignesh C <vignesh21@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Peter Smith <smithpb2250@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: 2024-12-31T07:05:10Z
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 Fri, Dec 27, 2024 at 9:22 AM vignesh C <vignesh21@gmail.com> wrote:
>
>
> Few comments:
> 1) We have disabled the similar configuration max_slot_wal_keep_size
> by setting to -1, as this GUC also is in similar lines, should we
> disable this and let the user configure it?
> +/*
> + * Invalidate replication slots that have remained idle longer than this
> + * duration; '0' disables it.
> + */
> +int                    idle_replication_slot_timeout_min =
> HOURS_PER_DAY * MINS_PER_HOUR;
> +
>

I’m okay with setting the default to either '1-day' or 'Off'. Let’s
wait for feedback from others.

>
> 2) I felt this behavior is an existing behavior, so this can also be
> moved to 0001 patch:
> diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
> index a586156614..199d7248ee 100644
> --- a/doc/src/sgml/system-views.sgml
> +++ b/doc/src/sgml/system-views.sgml
> @@ -2566,7 +2566,8 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
>        </para>
>        <para>
>          The time when the slot became inactive. <literal>NULL</literal> if the
> -        slot is currently being streamed.
> +        slot is currently being streamed. If the slot becomes invalidated,
> +        this value will remain unchanged until server shutdown.
>

You are correct that the 'inactive_since' value getting reset on
server restart has been the existing behavior.
However, earlier, there was no guarantee that it would remain
unchanged for invalid slots. The new function
"ReplicationSlotSetInactiveSince()" in patch 002, ensures that the
value does not change for invalidated slots until the server is shut
down. Therefore, I feel the doc addition in patch 002 is appropriate.

>
> 3) Can we change the comment below to "We don't allow the value of
> idle_replication_slot_timeout other than 0 during the binary upgrade.
> See start_postmaster() in pg_upgrade for more details.":
> + * The idle_replication_slot_timeout must be disabled (set to 0)
> + * during the binary upgrade.
> + */
> +bool
> +check_idle_replication_slot_timeout(int *newval, void **extra,
> GucSource source)

Done.

--
Thanks,
Nisha