On Mon, Apr 30, 2018 at 4:03 PM, Andres Freund <andres@anarazel.de> wrote:
>> Is this a problem in practice, though? I don't remember seeing any reports
>> of the fsync queue filling up, after we got the code to compact it. I don't
>> know if anyone has been looking for that, so that might also explain the
>> absence of reports, though.
>
> It's probably hard to diagnose that as the origin of slow IO from the
> outside. It's not exactly easy to diagnose that even if you know what's
> going on.
True, but has anyone ever actually observed a non-zero
pg_stat_bgwriter.buffers_backend_fsync in the wild after the
compaction queue stuff was added/backpatched?
--
Peter Geoghegan