po 18. 7. 2022 v 16:29 odesílatel Tom Lane <tgl@sss.pgh.pa.us> napsal:
Alvaro Herrera <alvherre@alvh.no-ip.org> writes: > On 2022-Jul-18, Pavel Stehule wrote: >> I am trying to fix one slow query, and found that optimization of min, max >> functions is possible only when there is no JOIN in the query.
> See preprocess_minmax_aggregates() in > src/backend/optimizer/plan/planagg.c > Maybe it is possible to hack that code so that this case can be handled > better.
The comments show this was already thought about:
* We also restrict the query to reference exactly one table, since join * conditions can't be handled reasonably. (We could perhaps handle a * query containing cartesian-product joins, but it hardly seems worth the * trouble.)
