Re: [PATCH] Expose checkpoint reason to completion log messages.

Hi,

On Thu, Jan 08, 2026 at 11:58:43AM +0530, Soumya S Murali wrote:
> On Wed, Jan 7, 2026 at 1:37 PM Michael Banck <mbanck(at)gmx(dot)net> wrote:
> > On Wed, Jan 07, 2026 at 12:35:08PM +0530, Soumya S Murali wrote:
> I have reworked the patch to factor out the checkpoint reason logic to
> use the same wording for both checkpoint start and completion log
> (including wal, time, fast, force, and wait). The format has been
> aligned with existing conventions and has been verified by running
> make check and recovery TAP tests including t/019_replslot_limit.pl
> successfully.
> Kindly review my patch and let me know the feedback.

Thanks for the new patch.

> index 22d0a2e8c3..9f7439f9a2 100644
> --- a/src/backend/access/transam/xlog.c
> +++ b/src/backend/access/transam/xlog.c
[...]
> +static const char *
> +CheckpointReasonString(int flags)
> +{
> + static char buf[128];
> +
> + buf[0] = '\0';
> +
> + if (flags & CHECKPOINT_IS_SHUTDOWN)
> + strcat(buf, " shutdown");
> + if (flags & CHECKPOINT_END_OF_RECOVERY)
> + strcat(buf, " end-of-recovery");
> + if (flags & CHECKPOINT_FAST)
> + strcat(buf, " fast");
> + if (flags & CHECKPOINT_FORCE)
> + strcat(buf, " force");
> + if (flags & CHECKPOINT_WAIT)
> + strcat(buf, " wait");
> + if (flags & CHECKPOINT_CAUSE_XLOG)
> + strcat(buf, " wal");
> + if (flags & CHECKPOINT_CAUSE_TIME)
> + strcat(buf, " time");
> + if (flags & CHECKPOINT_FLUSH_UNLOGGED)
> + strcat(buf, " flush-unlogged");
> +
> + return buf;
> +}

The way this is coded now prepends the final string with a space
character. This is fine for the checkpoint starting message, but makes
the checkpoint finished message look slightly weird (not the "( wal)"):

|2026-01-08 18:30:33.691 CET [1666416] LOG: checkpoint complete ( wal):
|wrote 20 buffers (0.1%), wrote 0 SLRU buffers; 0 WAL file(s) added, 4
|removed, 33 recycled; write=2.221 s, sync=0.019 s, total=2.701 s; sync
|files=3, longest=0.018 s, average=0.007 s; distance=601885 kB,
|estimate=601885 kB; lsn=0/D2D59FC8, redo lsn=0/B492B500

Also I think the translators might now complain, but I am not sure how
to best approach this.

Michael