Re: Removing unneeded self joins

Alexander Korotkov <aekorotkov@gmail.com>

From: Alexander Korotkov <aekorotkov@gmail.com>

To: Вардан Погосян <vardan.pogosyn@yandex.ru>

Cc: Andrei Lepikhov <lepihov@gmail.com>, jian he <jian.universality@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>, Andrei Lepikhov <a.lepikhov@postgrespro.ru>, Richard Guo <guofenglinux@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>

Date: 2024-07-16T14:30:47Z

Lists: pgsql-hackers

Commits

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Remove GUC_NOT_IN_SAMPLE from enable_self_join_elimination
- 717d0e8dd945 18.0 landed
Put enable_self_join_elimination into postgresql.conf.sample
- c2d329260cd8 18.0 landed
Get rid of ojrelid local variable in remove_rel_from_query()
- e167191dc146 18.0 landed
Implement Self-Join Elimination
- fc069a3a6319 18.0 cited
Revert: Remove useless self-joins
- d1d286d83c0e 17.0 landed
Replace lateral references to removed rels in subqueries
- 466979ef031a 17.0 landed
Replace relids in lateral subquery parse tree during SJE
- 489072ab7a9e 17.0 landed
Forbid SJE with result relation
- 8c441c082797 17.0 landed
Fix misuse of RelOptInfo.unique_for_rels cache by SJE
- 30b4955a4668 17.0 landed
Replace the relid in some missing fields during SJE
- a7928a57b9f0 17.0 landed
Revert 56-bit relfilenode change and follow-up commits.
- a448e49bcbe4 16.0 cited
Stabilize timetz test across DST transitions.
- 4a071afbd056 14.0 cited
Speed up finding EquivalenceClasses for a given set of rels
- 3373c7155350 13.0 cited
Fix mark-and-restore-skipping test case to not be a self-join.
- 24d08f3c0a1f 12.0 landed

Hi, Vardan!

Great, thank you!

On Tue, Jul 16, 2024 at 5:26 PM Вардан Погосян <vardan.pogosyn@yandex.ru> wrote:
> I did the SJE testing at Andrey's request.
> To do this, I used the automatic testing tool EET (Equivalent Expression Transformation) [1] with some modifications.
> EET transforms the logical conditions in a query, creating multiple queries waiting for the same number of rows.

What revision of patch did you use?

> In order to make sure that the SJE logic is executed at all, I tried to cover the code with ereports() as much as possible.

Could you share this?  Probably some of these ereports() we would like to keep.

> During the testing process, I did not find any inconsistencies in the number of rows returned, as well as other critical problems.

Did you use assert-enabled build?  I guess you mean no server crashes,
right?  Also, could you share some statistics on how long did you run,
what number of queries did you execute etc.?

------
Regards,
Alexander Korotkov
Supabase