Re: gistGetFakeLSN() can return incorrect LSNs

x4mmm@yandex-team.ru

From: Andrey Borodin <x4mmm@yandex-team.ru>

To: Andres Freund <andres@anarazel.de>

Cc: pgsql-hackers@postgresql.org, Noah Misch <noah@leadboat.com>, Tomas Vondra <tv@fuzzy.cz>, Peter Geoghegan <pg@bowt.ie>

Date: 2026-03-05T18:26:30Z

Lists: pgsql-hackers

Interesting bug. Your analysis seems correct to me.

> On 5 Mar 2026, at 22:10, Andres Freund <andres@anarazel.de> wrote:
> 
> To be safe, this code would need to use a version of GetXLogInsertRecPtr()
> that does use XLogBytePosToEndRecPtr() instead of XLogBytePosToRecPtr().

Can't we just take Insert->CurrBytePos without XLogBytePosToEndRecPtr()?
Is there a point in alignment before the page header?

Best regards, Andrey Borodin.

Commits

Use GetXLogInsertEndRecPtr in gistGetFakeLSN
- c0ffc725f8b3 14.23 landed
- ce06b5740ef9 15.18 landed
- 4f4025eac0b9 16.14 landed
- 6ef36bb35884 17.10 landed
- 5b3f63a1bf59 18.4 landed
- b1f14c967202 19 (unreleased) landed
Skip WAL for new relfilenodes, under wal_level=minimal.
- c6b92041d385 13.0 cited