Horton

Re: Shutdown indefinitely stuck due to unflushed FPI_FOR_HINT record

Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>

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From: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Alexander Lakhin <exclusion@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2026-03-16T09:45:35Z
Lists: pgsql-hackers 
On Mon, Mar 16, 2026 at 6:39 AM Fujii Masao <masao.fujii@gmail.com> wrote:
> Since Tomas added GetXLogInsertEndRecPtr() in commit b1f14c96720,
> I updated the patch to use it. Patch attached.
> Barring any objections, I will commit it.
>
> -       XLogFlush(GetXLogWriteRecPtr());
> +       XLogFlush(GetXLogInsertEndRecPtr());

Thanks for the updated patch! I've run my test script against the
patch and there's no more "xlog flush request xxx is not satisfied"
errors reported.

> I excluded the above change from the patch because it seems like a separate
> issue. I also wonder whether this code could cause an error in XLogFlush()
> even when GetXLogWriteRecPtr() is used.

Ha right, I've mixed Insert and Write and thought that
FinishSyncWorker was also doing a XlogFlush(GetXLogInsertRecPtr())
when writing the patch. If I try to trigger the partial record issue,
GetXLogWriteRecPtr() points at the end of the WAL page containing the
beginning of the FPI_FOR_HINT, there's no attempt to flush in the
future. So FinishSyncWorker doesn't seem impacted by the issue.

Regards,
Anthonin Bonnefoy

Commits

  1. Fix WAL flush LSN used by logical walsender during shutdown

  2. Use GetXLogInsertEndRecPtr in gistGetFakeLSN

  3. Fix publisher shutdown hang caused by logical walsender busy loop.