On 13/11/2020 18:10, Alexey Bashtanov wrote:
Hi,
I got somewhat scared when my explain took a few seconds to complete and
used a few gigs of RAM.
To reproduce try the following:
discard temp;
create temp table a as select to_timestamp(generate_series(1, 7000)) i;
analyze a;
set work_mem to '3GB';
explain select distinct a1.i - a2.i from a a1, a a2;
I would appreciate if someone could have a look at the patch attached,
which makes executor skip initializing hash tables when doing explain only.
Makes sense. Committed, thanks for the patch!
- Heikki
