Re: Suppressing useless wakeups in walreceiver

On Mon, Nov 14, 2022 at 11:08 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> There is something very seriously wrong with this patch.
>
> On my machine, running "make -j10 check-world" (with compilation
> already done) has been taking right about 2 minutes for some time.
> Since this patch, it's taking around 2:45 --- I did a bisect run
> to confirm that this patch is where it changed.
>
> The buildfarm is showing a hit, too. Comparing the step runtimes at
>
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=longfin&dt=2022-11-08%2005%3A29%3A28
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=longfin&dt=2022-11-08%2007%3A49%3A31
>
> it'd seem that most tests involving walreceivers got much slower:
> pg_basebackup-check from 00:29 to 00:39,
> pg_rewind-check went from 00:56 to 01:26,
> and recovery-check went from 03:56 to 04:45.
> Curiously, subscription-check only went from 03:26 to 03:29.
>
> I've not dug into it further than that, but my bet is that some
> required wakeup condition was not accounted for.

Looking...