On 23/8/2023 12:37, Richard Guo wrote:
To fix it we may need to modify RelOptInfos for Path, BitmapHeapPath,
ForeignPath and CustomPath, and modify IndexOptInfos for IndexPath. It
seems that that is not easily done without postponing reparameterization
of paths until createplan.c.
Attached is a patch which is v5 + fix for this new issue.
Having looked into the patch for a while, I couldn't answer to myself
for some stupid questions:
1. If we postpone parameterization until the plan creation, why do we
still copy the path node in the FLAT_COPY_PATH macros? Do we really need it?
2. I see big switches on path nodes. May it be time to create a
path_walker function? I recall some thread where such a suggestion was
declined, but I don't remember why.
3. Clause changing is postponed. Why does it not influence the
calc_joinrel_size_estimate? We will use statistics on the parent table
here. Am I wrong?
--
regards,
Andrey Lepikhov
Postgres Professional
