Re: Removing unneeded self joins - Mailing list pgsql-hackers

From Michał Kłeczek
Subject Re: Removing unneeded self joins
Date
Msg-id 88079CBD-B5BB-4C61-A68B-A8C67599E1C7@kleczek.org
Whole thread Raw
In response to Re: Removing unneeded self joins  (Andrey Lepikhov <a.lepikhov@postgrespro.ru>)
Responses Re: Removing unneeded self joins
List pgsql-hackers
Hi All,

I just wanted to ask about the status and plans for this patch.
I can see it being stuck at “Waiting for Author” status in several commit tests.

I think this patch would be really beneficial for us as we heavily use views to structure out code.
Each view is responsible for providing some calculated values and they are joined in a query to retrieve the full set
ofinformation. 

Not sure how the process works and how I could help (I am absolutely not capable of helping with coding I am afraid -
butcould sponsor a (small :) ) bounty to speed things up). 

Thanks,
Michal

> On 16 Dec 2022, at 07:45, Andrey Lepikhov <a.lepikhov@postgrespro.ru> wrote:
>
> On 12/6/22 23:46, Andres Freund wrote:
>> This doesn't pass the main regression tests due to a plan difference.
>> https://cirrus-ci.com/task/5537518245380096
>> https://api.cirrus-ci.com/v1/artifact/task/5537518245380096/testrun/build/testrun/regress/regress/regression.diffs
>> diff -U3 /tmp/cirrus-ci-build/src/test/regress/expected/join.out
/tmp/cirrus-ci-build/build/testrun/regress/regress/results/join.out
>> --- /tmp/cirrus-ci-build/src/test/regress/expected/join.out    2022-12-05 19:11:52.453920838 +0000
>> +++ /tmp/cirrus-ci-build/build/testrun/regress/regress/results/join.out    2022-12-05 19:15:21.864183651 +0000
>> @@ -5806,7 +5806,7 @@
>>   Nested Loop
>>     Join Filter: (sj_t3.id = sj_t1.id)
>>     ->  Nested Loop
>> -         Join Filter: (sj_t3.id = sj_t2.id)
>> +         Join Filter: (sj_t2.id = sj_t3.id)
>>           ->  Nested Loop Semi Join
>>                 ->  Nested Loop
>>                       ->  HashAggregate
> This change in the test behaviour is induced by the a5fc4641
> "Avoid making commutatively-duplicate clauses in EquivalenceClasses."
> Nothing special, as I see. Attached patch fixes this.
>
> --
> Regards
> Andrey Lepikhov
> Postgres Professional
> <v39-0001-Remove-self-joins.patch>




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