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Re: Pathify RHS unique-ification for semijoin planning - Mailing list pgsql-hackers

From Richard Guo
Subject Re: Pathify RHS unique-ification for semijoin planning
Date
Msg-id CAMbWs4-UXdxMaZO-GgNx7Y4tWoDutc4uVmnhUBn+8afHp520og@mail.gmail.com
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In response to Re: Pathify RHS unique-ification for semijoin planning  (Andrei Lepikhov <lepihov@gmail.com>)
Responses Re: Pathify RHS unique-ification for semijoin planning
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On Tue, Sep 2, 2025 at 7:56 PM Andrei Lepikhov <lepihov@gmail.com> wrote:
> No questions, it is good enough optimisation. I'm worried only about
> implementation: It creates one more RelOptInfo that may look like a
> baserel, but we can't find it by find_base_rel or even find_join_rel. It
> seems a little inconsistent to me.
> Don't think it is critical - just complicates life for extension
> developers in some cases.

The RelOptInfo representing the unique-ified rel is intended to be
used only internally during path generation for semi-joins, and should
be opaque outside of that.  I don't think extensions should know about
it.

- Richard

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