Hi,
On Tue, Aug 30, 2022 at 01:16:43PM +0200, Alvaro Herrera wrote:
> On 2022-Aug-30, Matheus Martin wrote:
>
> > Our Postgres recently started reporting considerably different
> > execution times for the same query. When executed from our JDBC
> > application the Postgres logs report an average execution time of 1500
> > ms but when the query is manually executed through `psql` it doesn't
> > take longer than 50 ms.
>
> I don't know why the plan is not saved by auto_explain (maybe we're
> missing ExecutorEnd calls somewhere? that would be strange), but one
> frequent reason for queries to show different plan in JDBC than psql is
> the use of prepared statements. Did you try using "PREPARE
> yourquery(...)" and then EXPLAIN EXECUTE(...)? Sometimes that helps to
> recreate the original problem.
>
> (Apparently, ExecutorEnd is called from PortalCleanup; what happens with
> the portal for an extended-protocol query?)
AFAICS log_min_duration_statements threshold is based on the full query
processing time while auto_explain is only based on the executor runtime, so
one more likely explanation is that out of the 1423ms, more than 423ms were
spent in the planner?
