Re: too high planning time

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