Re: walsummarizer can get stuck when switching timelines - Mailing list pgsql-hackers

On Thu, 16 Jul 2026 at 14:45, Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Thu, Jul 16, 2026 at 8:59 AM Thom Brown <thom@linux.com> wrote:
> > Well if we run pg_switch_wal(), we're effectively closing the current
> > segment. CHECKPOINT then emits its WAL after the switch. If the
> > summarizer needs a CHECKPOINT_REDO record in the segment being
> > archived, it would already be too late.
>
> OK, I think this is where we're seeing things differently. The
> summarizer doesn't need a CHECKPOINT_REDO record in the segment being
> archived. Rather, we need a CHECKPOINT_REDO record somewhere after the
> WAL that we want summarized. In this case, the WAL we want summarized
> is generated by the pg_switch_wal() call.

Ah, gotcha. Sorry for the noise.

Thom