On Mon, May 12, 2025 at 6:33 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
Maxim Boguk <maxim.boguk@xxxxxxxxx> writes:
> And the problem is that the cost of a custom plan ignores the cost of
> planning itself (which is like 2x orders of magnitude worse than the cost
> of real time partition pruning of a generic plan).
False. The estimate is evidently pretty wrong, but it's not that
there is no consideration at all. See around line 1370 in
src/backend/utils/cache/plancache.c.
regards, tom lane
Thank you.
Reading the code - probably the lowest hanging fruit is to make
'The current multiplier of 1000 * cpu_operator_cost' configurable in the future versions.
PS: it's always nice to see when my ad-hoc idea (about N*nrelations as cost planner estimate) is already implemented.
Maxim Boguk
Senior Postgresql DBA
Phone UA: +380 99 143 0000
Phone AU: +61 45 218 5678
Senior Postgresql DBA
Phone UA: +380 99 143 0000
Phone AU: +61 45 218 5678
