RE: Newly created replication slot may be invalidated by checkpoint

Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>

From: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>

To: 'Amit Kapila' <amit.kapila16@gmail.com>, Vitaly Davydov <v.davydov@postgrespro.ru>

Cc: suyu.cmj <mengjuan.cmj@alibaba-inc.com>, aekorotkov <aekorotkov@gmail.com>, tomas <tomas@vondra.me>, michael <michael@paquier.xyz>, bharath.rupireddyforpostgres <bharath.rupireddyforpostgres@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2025-09-24T11:31:22Z

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 →

Prevent invalidation of newly synced replication slots.
- 3243c0177efb 17.8 landed
- 919c9fa13cd0 18.2 landed
- 851f6649cc18 19 (unreleased) landed
Prevent invalidation of newly created replication slots.
- 3510ebeb0dfa 17.8 landed
- 24cce33c332a 16.12 landed
- aae05622a7cb 15.16 landed
- 7406df60569f 14.21 landed
- d3ceb20846e4 18.2 landed
- 006dd4b2e5b3 19 (unreleased) landed
Fix re-distributing previously distributed invalidation messages during logical decoding.
- 45c357e0e85d 17.6 cited
Keep WAL segments by the flushed value of the slot's restart LSN
- 2090edc6f32f 17.6 cited
Keep WAL segments by slot's last saved restart LSN
- ca307d5cec90 18.0 cited

Attachments

0001-Stop-using-injection_points-for-checkpointer.patch (application/octet-stream) patch 0001

Dear Amit, Vitaly,

> I was thinking some more about this solution. Won't it lead to the
> same problem if ReplicationSlotReserveWal() calls
> ReplicationSlotsComputeRequiredLSN() after the above calculation of
> checkpointer?

Exactly. I verified that in your patch, the invalidation can still happen if we
cannot finish the LSN computation before the KeepLogSegments().

Attached file can be applied atop 0001-Fix-invalidation-... and
v2-17-0001-Newly-created-replication... patches. It could invalidate the given
slot.

Best regards,
Hayato Kuroda
FUJITSU LIMITED