Re: Slow statement using parallelism after 9.6>11 upgrade

Le 03/09/2019 à 15:43, Tom Lane a écrit :
> "Arnaud L." <arnaud.listes@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.

Cheers
--
Arnaud