Re: Replication conflicts despite hot_standby_feedback = on?

On Wed, Jun 3, 2020 at 2:05 PM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> wrote:
>
> On Wed, 2020-06-03 at 13:41 +0200, Julien Rouhaud wrote:
> > > I'm seeing the following at a customer site:
> > >
> > > SELECT confl_tablespace, confl_lock, confl_snapshot, confl_bufferpin, confl_deadlock
> > > FROM pg_stat_database_conflicts
> > > WHERE datname = 'something' \gx
> > >
> > > -[ RECORD 1 ]----+------
> > > confl_tablespace | 0
> > > confl_lock | 0
> > > confl_snapshot | 84990
> > > confl_bufferpin | 0
> > > confl_deadlock | 0
> > >
> > > SHOW hot_standby_feedback;
> > >
> > > hot_standby_feedback
> > > ----------------------
> > > on
> > > (1 row)
> >
> > One of the frequent causes is the lock acquired by (auto)vacuum when
> > truncating the trailing empty blocks, maybe you can correlate your
> > conflicts with autovacuum activity?
>
> Yes, but that would show up as a lock conflict, not a snapshot conflict,
> right?

Oh yes indeed, sorry for the noise.