Horton

Re: Support "Right Semi Join" plan shapes

wenhui qiu <qiuwenhuifx@gmail.com>

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From: wenhui qiu <qiuwenhuifx@gmail.com>
To: Richard Guo <guofenglinux@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2024-03-04T02:33:00Z
Lists: pgsql-hackers

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  1. Support "Right Semi Join" plan shapes

  2. Fix neqjoinsel's behavior for semi/anti join cases.

HI Richard
     Now it is starting the last commitfest for v17, can you respond to
Alena Rybakina points?


Regards

On Thu, 8 Feb 2024 at 13:50, wenhui qiu <qiuwenhuifx@gmail.com> wrote:

> Hi Alena Rybakina
>  I saw this code snippet also disable mergejoin ,I think it same  effect
> + /*
> + * For now we do not support RIGHT_SEMI join in mergejoin.
> + */
> + if (jointype == JOIN_RIGHT_SEMI)
> + {
> + *mergejoin_allowed = false;
> + return NIL;
> + }
> +
>
> Regards
>
> Alena Rybakina <lena.ribackina@yandex.ru> 于2024年1月30日周二 14:51写道：
>
>> Hi! Thank you for your work on this subject.
>>
>> I have reviewed your patch and I think it is better to add an Assert for
>> JOIN_RIGHT_SEMI to the ExecMergeJoin and ExecNestLoop functions to
>> prevent the use of RIGHT_SEMI for these types of connections (NestedLoop
>> and MergeJoin).
>> Mostly I'm suggesting this because of the set_join_pathlist_hook
>> function, which is in the add_paths_to_joinrel function, which allows
>> you to create a custom node. What do you think?
>>
>> --
>> Regards,
>> Alena Rybakina
>> Postgres Professional: http://www.postgrespro.com
>> The Russian Postgres Company
>>
>>