Re: Removing unneeded self joins

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

From: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
To: Richard Guo <guofenglinux@gmail.com>
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Alexander Lakhin <exclusion@gmail.com>, "Gregory Stark (as CFM)" <stark.cfm@gmail.com>, Michał Kłeczek <michal@kleczek.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2024-02-21T07:59:45Z
Lists: pgsql-hackers

Commits

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  1. Remove GUC_NOT_IN_SAMPLE from enable_self_join_elimination

  2. Put enable_self_join_elimination into postgresql.conf.sample

  3. Get rid of ojrelid local variable in remove_rel_from_query()

  4. Implement Self-Join Elimination

  5. Revert: Remove useless self-joins

  6. Replace lateral references to removed rels in subqueries

  7. Replace relids in lateral subquery parse tree during SJE

  8. Forbid SJE with result relation

  9. Fix misuse of RelOptInfo.unique_for_rels cache by SJE

  10. Replace the relid in some missing fields during SJE

  11. Revert 56-bit relfilenode change and follow-up commits.

  12. Stabilize timetz test across DST transitions.

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

  14. Fix mark-and-restore-skipping test case to not be a self-join.

On 21/2/2024 14:26, Richard Guo wrote:
> This patch also includes some cosmetic tweaks for SJE test cases.  It
> does not change the test cases using catalog tables though.  I think
> that should be a seperate patch.
Thanks for this catch, it is really messy thing, keeping aside the 
question why we need two different subtrees for the same query.
I will look into your fix.

-- 
regards,
Andrei Lepikhov
Postgres Professional