Re: Removing unneeded self joins

Alexander Korotkov <aekorotkov@gmail.com>

From: Alexander Korotkov <aekorotkov@gmail.com>
To: Alexander Lakhin <exclusion@gmail.com>
Cc: Andrei Lepikhov <a.lepikhov@postgrespro.ru>, "Gregory Stark (as CFM)" <stark.cfm@gmail.com>, Michał Kłeczek <michal@kleczek.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Richard Guo <guofenglinux@gmail.com>
Date: 2024-02-18T15:04:17Z
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 Sun, Feb 18, 2024 at 3:00 PM Alexander Lakhin <exclusion@gmail.com> wrote:
> 09.01.2024 01:09, Alexander Korotkov wrote:
>
> Fixed in 30b4955a46.
>
>
> Please look at the following query which fails with an error since
> d3d55ce57:
>
> create table t (i int primary key);
>
> select t3.i from t t1
>  join t t2 on t1.i = t2.i,
>  lateral (select t1.i limit 1) t3;
>
> ERROR:  non-LATERAL parameter required by subquery

Thank you for spotting.  I'm looking at this.

------
Regards,
Alexander Korotkov