Re: Removing unneeded self joins

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

From: Andrei Lepikhov <a.lepikhov@postgrespro.ru>

To: Alexander Korotkov <aekorotkov@gmail.com>, Alexander Lakhin <exclusion@gmail.com>

Cc: "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: 2024-02-19T05:24:09Z

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 →

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

Attachments

0001-Replace-relids-in-lateral-subquery-target-list-du-v2.patch (text/plain) patch v2-0001

On 18/2/2024 23:18, Alexander Korotkov wrote:
> On Sun, Feb 18, 2024 at 5:04 PM Alexander Korotkov <aekorotkov@gmail.com> wrote:
>> 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.
> 
> Attached is a draft patch fixing this query.  Could you, please, recheck?
I reviewed this patch. Why do you check only the target list? I guess 
these links can be everywhere. See the patch in the attachment with the 
elaborated test and slightly changed code.

-- 
regards,
Andrei Lepikhov
Postgres Professional