Re: Introduce XID age and inactive timeout based replication slot invalidation
Peter Smith <smithpb2250@gmail.com>
Commits
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API reference →
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Add a test for commit ac0e33136a using the injection point.
- 8a695d7998be 18.0 landed
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Invalidate inactive replication slots.
- ac0e33136abc 18.0 landed
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Fix incorrect slot type in BuildTupleHashTableExt
- d96d1d5152f3 18.0 cited
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Allow synced slots to have their inactive_since.
- 6f132ed693b6 17.0 landed
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Change last_inactive_time to inactive_since in pg_replication_slots.
- 6d49c8d4b4f4 17.0 landed
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Track last_inactive_time in pg_replication_slots.
- a11f330b5584 17.0 landed
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Track invalidation_reason in pg_replication_slots.
- 6ae701b4378d 17.0 landed
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Add option force_initdb to PostgreSQL::Test::Cluster:init()
- ff9e1e764fcc 17.0 cited
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Add a failover option to subscriptions.
- 776621a5e479 17.0 cited
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Allow setting failover property in the replication command.
- 73292404370c 17.0 cited
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Allow to enable failover property for replication slots via SQL API.
- c393308b69d2 17.0 cited
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Track conflict_reason in pg_replication_slots.
- 007693f2a3ac 17.0 cited
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Log messages for replication slot acquisition and release.
- 7c3fb505b14e 17.0 cited
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Remove vacuum_defer_cleanup_age
- 1118cd37eb61 16.0 cited
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Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids
- be504a3e974d 16.0 cited
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meson: Add initial version of meson based build system
- e6927270cd18 16.0 cited
Attachments
- PS_NITPICKS_20240909_TIMEOUT_V450001.txt (text/plain)
Hi, here are some review comments for v45-0001 (excluding the test code)
======
doc/src/sgml/config.sgml
1.
+ Note that the inactive timeout invalidation mechanism is not
+ applicable for slots on the standby server that are being synced
+ from primary server (i.e., standby slots having
nit - /from primary server/from the primary server/
======
src/backend/replication/slot.c
2. ReplicationSlotAcquire
+ errmsg("can no longer get changes from replication slot \"%s\"",
+ NameStr(s->data.name)),
+ errdetail("This slot has been invalidated because it was inactive
for longer than the amount of time specified by \"%s\".",
+ "replication_slot_inactive_timeout.")));
nit - "replication_slot_inactive_timeout." - should be no period
inside that GUC name literal
~~~
3. ReportSlotInvalidation
I didn't understand why there was a hint for:
"You might need to increase \"%s\".", "max_slot_wal_keep_size"
But you don't have an equivalent hint for timeout invalidation:
"You might need to increase \"%s\".", "replication_slot_inactive_timeout"
Why aren't these similar cases consistent?
~~~
4. RestoreSlotFromDisk
+ /* Use the same inactive_since time for all the slots. */
+ if (now == 0)
+ now = GetCurrentTimestamp();
+
Is the deferred assignment really necessary? Why not just
unconditionally assign the 'now' just before the for-loop? Or even at
the declaration? e.g. The 'replication_slot_inactive_timeout' is
measured in seconds so I don't think 'inactive_since' being wrong by a
millisecond here will make any difference.
======
src/include/replication/slot.h
5. ReplicationSlotSetInactiveSince
+/*
+ * Set slot's inactive_since property unless it was previously invalidated due
+ * to inactive timeout.
+ */
+static inline void
+ReplicationSlotSetInactiveSince(ReplicationSlot *s, TimestampTz *now,
+ bool acquire_lock)
+{
+ if (acquire_lock)
+ SpinLockAcquire(&s->mutex);
+
+ if (s->data.invalidated != RS_INVAL_INACTIVE_TIMEOUT)
+ s->inactive_since = *now;
+
+ if (acquire_lock)
+ SpinLockRelease(&s->mutex);
+}
Is the logic correct? What if the slot was already invalid due to some
reason other than RS_INVAL_INACTIVE_TIMEOUT? Is an Assert needed?
======
Kind Regards,
Peter Smith.
Fujitsu Australia