Horton

Re: Performance issue in foreign-key-aware join estimation

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Tomas Vondra <tomas.vondra@2ndquadrant.com>
Date: 2019-02-21T02:00:33Z
Lists: pgsql-hackers

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David Rowley <david.rowley@2ndquadrant.com> writes:
> Attaching the original patch again so the commitfest bot gets off my
> back about the other one not applying.

Pushed that one.  I'm interested by the "POC" patch, but I agree
that it'd take some research to show that it isn't a net negative
for simple queries.  It sounds like you're not really interested
in pursuing that right now?

Anyway, I rebased the POC patch up to HEAD, just in case anyone
still wants to play with it.

			regards, tom lane

Commits

  1. Adjust overly strict Assert

  2. Speed up finding EquivalenceClasses for a given set of rels

  3. Speed up match_eclasses_to_foreign_key_col() when there are many ECs.