On Mon, Apr 30, 2018 at 4:03 PM, Andres Freund <and...@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
