Hi Bruce,
On Fri, Jun 26, 2020 at 3:24 PM Bruce Momjian <bruce@momjian.us> wrote:
> Patch attached and applied to PG 13.
I committed the hash_mem_multiplier GUC to Postgres 13 just now.
There should be a note about this in the Postgres 13 release notes,
for the usual reasons. More importantly, the "Allow hash aggregation
to use disk storage for large aggregation result sets" feature should
reference the new GUC directly. Users should be advised that the GUC
may be useful in cases where they upgrade and experience a performance
regression linked to slower hash aggregation. Just including a
documentation link for the GUC would be very helpful.
Thanks
--
Peter Geoghegan