> On Sep 3, 2019, at 7:06 AM, Arnaud L. <arnaud.lis...@codata.eu> wrote:
>
> Le 03/09/2019 à 15:43, Tom Lane a écrit :
>> "Arnaud L." <arnaud.lis...@codata.eu> writes:
>>> We have upgraded our database from 9.6 to 11 (and updated PostGIS from 2.3
>>> to 2.5 as well).
>>> ...
>> Have you re-ANALYZEd the database? The problem with this query
>> seems to be the spectacularly awful rowcount estimate here:
>
> You mean after the upgrade process ? Yes I have.
> I've juste re-run "ANALYZE table" to rule this out, estimates are the same.
>
> Maybe some statistic target problem ? Estimated number of rows is 284.196.352
> Also, this is a GIN index on a bigint[] column.
>
> I've setup parallel_tuple_cost to 1.0 parallel_setup_cost to 5000.0 for the
> time being which solves this specific problem. These value don't look very
> sensible though, they are very high compared to the default ones.
You can also leave that setting unchanged and just change the behaviour on your
one table:
ALTER TABLE nodes SET ( parallel_workers = 0);
P.
>
> Cheers
> --
> Arnaud
>
>
