Re: Removing unneeded self joins

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

From: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
To: Laurenz Albe <laurenz.albe@cybertec.at>, Hywel Carver <hywel@skillerwhale.com>, pgsql-hackers@lists.postgresql.org
Cc: Konstantin Knizhnik <knizhnik@garret.ru>
Date: 2021-07-01T05:20:24Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  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 30/6/21 18:55, Laurenz Albe wrote:
> On Wed, 2021-06-30 at 14:21 +0300, Andrey Lepikhov wrote:
>> I think, here we could ask more general question: do we want to remove a
>> 'IS NOT NULL' clause from the clause list if the rest of the list
>> implicitly implies it?
> Generally I have the impression that we are not too keen on spending
> planning time on optimizing cases that can be trivially improved by rewriting
> the query.
Thank you, It's strong argument.
Such feature would look better as a part of an enterprise edition.

-- 
regards,
Andrey Lepikhov
Postgres Professional