Re: Introduce XID age and inactive timeout based replication slot invalidation
vignesh C <vignesh21@gmail.com>
From: vignesh C <vignesh21@gmail.com>
To: Nisha Moond <nisha.moond412@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>,
Shlok Kyal <shlok.kyal.oss@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: 2025-02-04T11:11:47Z
Lists: pgsql-hackers
Commits
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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 Tue, 4 Feb 2025 at 15:58, Nisha Moond <nisha.moond412@gmail.com> wrote:
>
> Here are the v68 patches, incorporating above as well as comments from [1].
>
Few comments:
1) Let's call TimestampDifferenceExceedsSeconds only if
idle_replication_slot_timeout_mins is set to avoid the
TimestampDifferenceExceedsSeconds function call and timestamp diff
calculation if not required:
+ if (CanInvalidateIdleSlot(s) &&
+ TimestampDifferenceExceedsSeconds(s->inactive_since, now,
+ idle_replication_slot_timeout_mins * SECS_PER_MINUTE))
+ {
+ invalidation_cause = cause;
+ inactive_since = s->inactive_since;
+ }
+ break;
2) Let's keep the prototype after TimestampDifferenceExceeds to keep
it consistent with the source file and will also make it easy to
search:
diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index d26f023fb8..e1d05d6779 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -143,5 +143,8 @@ extern int date2isoyear(int year, int mon, int mday);
extern int date2isoyearday(int year, int mon, int mday);
extern bool TimestampTimestampTzRequiresRewrite(void);
+extern bool TimestampDifferenceExceedsSeconds(TimestampTz start_time,
+
TimestampTz stop_time,
+
int threshold_sec);
3)How about we change the below:
+#ifdef USE_INJECTION_POINTS
+
+ /*
+ * To test idle
timeout slot invalidation, if the
+ * slot-time-out-inval
injection point is attached,
+ * set inactive_since
to a very old timestamp (1
+ * microsecond since
epoch) to immediately invalidate
+ * the slot.
+ */
+ if
(IS_INJECTION_POINT_ATTACHED("slot-time-out-inval"))
+ s->inactive_since = 1;
+#endif
to:
#ifdef USE_INJECTION_POINTS
/*
* To test idle timeout slot invalidation, if the
* slot-time-out-inval injection point is attached,
* set inactive_since to current time and invalidate the slot immediately.
*/
if (IS_INJECTION_POINT_ATTACHED("slot-time-out-inval") &&
idle_replication_slot_timeout_mins)
{
invalidation_cause = cause;
inactive_since = s->inactive_since = now;
}
#else
/*
* Check if the slot needs to be invalidated due to
* idle_replication_slot_timeout GUC.
*/
if (TimestampDifferenceExceedsSeconds(s->inactive_since, now,
idle_replication_slot_timeout_mins * SECS_PER_MINUTE))
{
invalidation_cause = cause;
inactive_since = s->inactive_since;
}
#endif
We can just invalidate the slot directly without checking the time
difference if idle_replication_slot_timeout_mins is set and
inactive_since can hold the now value.
Regards,
Vignesh