Re: Big performance slowdown from 11.2 to 13.3 - Mailing list pgsql-performance

Justin Pryzby <pryzby@telsasoft.com> writes:
> Oh.  So the problem seems to be that:

> 1) In v12, HashAgg now obeyes work_mem*hash_mem_multiplier;
> 2) Under windows, work_mem is limited to 2GB.

And more to the point, work_mem*hash_mem_multiplier is *also* limited
to 2GB.  We didn't think that through very carefully.  The point of
the hash_mem_multiplier feature was to allow hash aggregation to still
consume more than the work_mem limit, but we failed to free it from
this 2GB limit.

You're right though that this is Windows-only; on machines with
64-bit "long" there's less of a problem.

            regards, tom lane