po 18. 7. 2022 v 16:29 odesÃlatel Tom Lane <t...@sss.pgh.pa.us> napsal:
> Alvaro Herrera <alvhe...@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.) > > Thank you for reply Regards Pavel > regards, tom lane >
