Re: Replication conflicts despite hot_standby_feedback = on?

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?

Yours,
Laurenz Albe