From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Remove some redundant set_cheapest() calls
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Comments: In-reply-to Richard Guo <guofenglinux@gmail.com>
	message dated "Tue, 26 Mar 2024 19:02:48 +0800"
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Date: Tue, 26 Mar 2024 16:06:58 -0400
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Richard Guo <guofenglinux@gmail.com> writes:
> I happened to notice that the set_cheapest() calls in functions
> set_namedtuplestore_pathlist() and set_result_pathlist() are redundant,
> as we've centralized the set_cheapest() calls in set_rel_pathlist().

> Attached is a trivial patch to remove these calls.

Agreed, and pushed.

> BTW, I suspect that the set_cheapest() call in set_dummy_rel_pathlist()
> is also redundant.  The comment there says "This is redundant when we're
> called from set_rel_size(), but not when called from elsewhere".  I
> doubt it.  The other places where it is called are set_append_rel_size()
> and set_subquery_pathlist(), both being called from set_rel_size().  So
> set_cheapest() would ultimately be called in set_rel_pathlist().

I'm less convinced about changing this.  I'd rather keep it consistent
with mark_dummy_rel.

			regards, tom lane