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: Nisha Moond <nisha.moond412@gmail.com>
Cc: Peter Smith <smithpb2250@gmail.com>, vignesh C <vignesh21@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: 2024-12-20T09:42:06Z
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 Mon, Dec 16, 2024 at 4:10 PM Nisha Moond <nisha.moond412@gmail.com> wrote:
>
> Here is the v56 patch set with the above comments incorporated.
>

Review comments:
===============
1.
+ {
+ {"idle_replication_slot_timeout", PGC_SIGHUP, REPLICATION_SENDING,
+ gettext_noop("Sets the duration a replication slot can remain idle before "
+ "it is invalidated."),
+ NULL,
+ GUC_UNIT_MS
+ },
+ &idle_replication_slot_timeout_ms,

I think users are going to keep idele_slot timeout at least in hours.
So, millisecond seems the wrong choice to me. I suggest to keep the
units in minutes. I understand that writing a test would be
challenging as spending a minute or more on one test is not advisable.
But I don't see any test testing the other GUCs that are in minutes
(wal_summary_keep_time and log_rotation_age). The default value should
be one day.

2.
+ /*
+ * An error is raised if error_if_invalid is true and the slot is found to
+ * be invalid.
+ */
+ if (error_if_invalid && s->data.invalidated != RS_INVAL_NONE)
+ {
+ StringInfoData err_detail;
+
+ initStringInfo(&err_detail);
+
+ switch (s->data.invalidated)
+ {
+ case RS_INVAL_WAL_REMOVED:
+ appendStringInfo(&err_detail, _("This slot has been invalidated
because the required WAL has been removed."));
+ break;
+
+ case RS_INVAL_HORIZON:
+ appendStringInfo(&err_detail, _("This slot has been invalidated
because the required rows have been removed."));
+ break;
+
+ case RS_INVAL_WAL_LEVEL:
+ /* translator: %s is a GUC variable name */
+ appendStringInfo(&err_detail, _("This slot has been invalidated
because \"%s\" is insufficient for slot."),
+ "wal_level");
+ break;
+
+ case RS_INVAL_NONE:
+ pg_unreachable();
+ }
+
+ ereport(ERROR,
+ errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("can no longer get changes from replication slot \"%s\"",
+    NameStr(s->data.name)),
+ errdetail_internal("%s", err_detail.data));
+ }
+

This should be moved to a separate function.

3.
+static inline bool
+IsSlotIdleTimeoutPossible(ReplicationSlot *s)

Would it be better to name this function as CanInvalidateIdleSlot()?
The current name doesn't seem to match with similar other
functionalities.

-- 
With Regards,
Amit Kapila.