From 3b1d44983d08403328f4b42698f35a4ed1f681ca Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Wed, 18 Jun 2025 19:34:00 +0300 Subject: [PATCH v5] Remove excess assert from InvalidatePossiblyObsoleteSlot() ca307d5cec90 introduced keeping WAL segments by slot's last saved restart LSN. It also added an assertion that the slot's restart LSN never goes backward. However, situations when the restart LSN goes backward have been spotted by buildfarm animals and investigated in the thread. When pg_receivewal starts the replication, it sets the last replayed LSN to the beginning of the segment, which is older than what ReplicationSlotReserveWal() set for the slot. When standby reconnects to the primary, it sends the last replayed LSN, which might be older than the last confirmed flush LSN. In both these situations, a concurrent checkpoint may trigger an assert trap. Based on ideas from Vitaly Davydov , Hayato Kuroda (Fujitsu) , vignesh C , Amit Kapila . Reported-by: Vignesh C Reported-by: Tom Lane Discussion: https://postgr.es/m/CALDaNm3s-jpQTe1MshsvQ8GO%3DTLj233JCdkQ7uZ6pwqRVpxAdw%40mail.gmail.com --- src/backend/replication/slot.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index c64f020742f..c11e588d632 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -1810,8 +1810,6 @@ InvalidatePossiblyObsoleteSlot(uint32 possible_causes, */ SpinLockAcquire(&s->mutex); - Assert(s->data.restart_lsn >= s->last_saved_restart_lsn); - restart_lsn = s->data.restart_lsn; /* we do nothing if the slot is already invalid */ -- 2.39.5 (Apple Git-154)