On 25/8/2023 14:39, Yuya Watari wrote:
Hello,
On Wed, Aug 9, 2023 at 8:54 PM David Rowley <dgrowle...@gmail.com> wrote:
I think the best way to move this forward is to explore not putting
partitioned table partitions in EMs and instead see if we can
translate to top-level parent before lookups. This might just be too
complex to translate the Exprs all the time and it may add overhead
unless we can quickly determine somehow that we don't need to attempt
to translate the Expr when the given Expr is already from the
top-level parent. If that can't be made to work, then maybe that shows
the current patch has merit.
Based on your suggestion, I have experimented with not putting child
EquivalenceMembers in an EquivalenceClass. I have attached a new
patch, v20, to this email. The following is a summary of v20.
Working on self-join removal in the thread [1] nearby, I stuck into the
problem, which made an additional argument to work in this new direction
than a couple of previous ones.
With indexing positions in the list of equivalence members, we make some
optimizations like join elimination more complicated - it may need to
remove some clauses and equivalence class members.
For changing lists of derives or ec_members, we should go through all
the index lists and fix them, which is a non-trivial operation.
[1]
https://www.postgresql.org/message-id/flat/64486b0b-0404-e39e-322d-0801154901f3%40postgrespro.ru
--
regards,
Andrey Lepikhov
Postgres Professional
