Re: too high planning time

pg_stat_activity is the place to look.

This tells you all of the blocked pids:
SELECT pid
     , username
     , pg_blocking_pids(pid) AS blocked_by
     , left(query, 100) as blocked_query
FROM pg_stat_activity
WHERE CARDINALITY(blocking_pids(pid)) > 0;

From there, you can see what the blocking pid is doing.

On 2/2/23 12:21, Kenny Bachman wrote:
> In fact, when I run the query for the second time, it returns very fast
> results. But after a while the problem reoccurs.
> Not just for these queries, but almost all queries in the database are
> slowed down this way.
> Is it normal to have a lock on the catalog or system tables? What should I
> do when this happens on pg_statistic or other catalogs?
>
> thanks a lot for your comments and help
> Kenny
>
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, 2 Şub 2023 Per, 18:24 tarihinde şunu yazdı:
>
> Kenny Bachman <kenny(dot)bachman17(at)gmail(dot)com> writes:
> > EXPLAIN ANALYZE select
> >     i."DefinitionId",
> > from
> >     "T_WF_INSTANCE" i
> > where
> >     i."InstanceId" = 10045683193;
>
> >        QUERY PLAN
>
> >
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> >  Index Scan using
> > "T_WF_INSTANCE_InstanceId_ApplicationCd_EntityStatusCd_idx" on
> > "T_WF_INSTANCE" i  (cost=0.57..2.79 rows=1 width=34) (actual
> > time=2.522..2.522 rows=1 loops=1)
> >    Index Cond: ("InstanceId" = '10045683193'::bigint)
>
> > * Planning Time: 8460.446 ms Execution Time: 2.616 ms*
> > (4 rows)
>
> It's hard to believe that such a simple query could take that
> long to plan.  What I'm wondering is if the planner got blocked
> on some other session's exclusive lock.  Not a lock on
> "T_WF_INSTANCE" itself, because we'd have got that lock during
> parsing before the "Planning Time" measurement starts.  But
> there's going to be a physical access to the table's index
> to determine its tree height, so an ex-lock on the index could
> explain this.  Or an ex-lock on catalogs, particularly pg_statistic.
> What else is going on in your database when this happens?
>
>                         regards, tom lane
>

--
Born in Arizona, moved to Babylonia.