Re: [External] Re: FDW, too long to run explain

Ok.
I’ll try to work on it this week and see if i am able to reproduce anything.

On Mon, 18 Feb 2019 at 2:30 AM Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:

>
>
> On Sun, Feb 17, 2019 at 2:37 PM Vijaykumar Jain <vjain(at)opentable(dot)com>
> wrote:
>
>>
>> Ok, i raked this from the logs where enabled log_min_duration_statement =
>> 10s
>>
>> 2019-01-31 12:48:18 UTC LOG: duration: 29863.311 ms statement: EXPLAIN
>> SELECT blah, FROM public.view WHERE ((scheduled_bdt >= '2019-01-20'::date))
>> AND ((scheduled_bdt <= '2019-01-26'::date)) AND ((somekey = ANY
>> ('{269029,123399,263164,261487}'::bigint[]))) (both the columns are
>> indexed)
>>
>
> That is interesting. Was that in the logs for the local or the foreign
> side? And is it common, or rare?
>
> If on the local side, could it be that the EXPLAINs sent to the foreign
> side are being made to wait by the connection pooler, leading to long
> delays? If that is from the foreign side, then it should be conceptually
> unrelated to FDW. Any chance you could reproduce the slowness in your test
> environment? Slowness in the planner is probably related to the schema
> structure, not the data itself.
>
> I don't think this would be related to the idle-in-transaction, except
> that one FDW connection maybe idle-in-transaction after its EXPLAIN is done
> because it is waiting for another FDW connection to slowly run its EXPLAIN.
>
> Cheers,
>
> Jeff
>
>> --

Regards,
Vijay