Horton

Re: A performance issue with Memoize

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Richard Guo <guofenglinux@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2024-01-26T20:41:58Z
Lists: pgsql-hackers 
David Rowley <dgrowleyml@gmail.com> writes:
> I've adjusted the comments to what you mentioned and also leaned out
> the pretty expensive test case to something that'll run much faster
> and pushed the result.

drongo and fairywren are consistently failing the test case added
by this commit.  I'm not quite sure why the behavior of Memoize
would be platform-specific when we're dealing with integers,
but ...

			regards, tom lane

Commits

  1. Attempt to fix newly added Memoize regression test

  2. Compare varnullingrels too in assign_param_for_var().

  3. De-dupicate Memoize cache keys

  4. Improve NestLoopParam generation for lateral subqueries

  5. Avoid sharing PARAM_EXEC slots between different levels of NestLoop.