Re: Slow statement using parallelism after 9.6>11 upgrade

Le 03/09/2019 à 17:02, Imre Samu a écrit :
> > We have upgraded our database from 9.6 to 11
>
> This is now the latest PG ?   PG11.5?

Yes, PostgreSQL 11.5, compiled by Visual C++ build 1914, 64-bit.

> - the osm2pgsql has an own parallelizations ...  ( osm2pgsql
> --number-processes .. )
>    so be careful to add more parallelisation to the PG side with the
> same osm2pgsql parameters !   ( check the memory usages! )
> - check the benchmarks and the tunnings:
> https://wiki.openstreetmap.org/wiki/Osm2pgsql/benchmarks
> - you can ask help on the  : "osm dev mail list" (="dev OpenStreetMap
> developer discusssion" https://lists.openstreetmap.org/listinfo/dev )

Yes, I know. It as been fine tuned over some time now to fit our
server's capacity.
Disabling parallelisme has allowed the update to run in ~5000s, which is
consistent with what we could witness before the upgrade.

I had started writing an issue on the osm2pgsql github before realizing
it was probably a PG-only issue.

Cheers
--
Arnaud