From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
cc: xinwen@stu.scu.edu.cn, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17700: An assert failed in prepjointree.c
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Comments: In-reply-to Richard Guo <guofenglinux@gmail.com>
	message dated "Mon, 28 Nov 2022 20:32:15 +0800"
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Date: Mon, 28 Nov 2022 10:33:37 -0500
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Richard Guo <guofenglinux@gmail.com> writes:
> I haven't got too much time looking into it.  But the comment near the
> assertion failure that says

>  * Unlike the LEFT/RIGHT cases, we just Assert that there are
>  * no PHVs that need to be evaluated at the semijoin's RHS,
>  * since the rest of the query couldn't reference any outputs
>  * of the semijoin's RHS.

> I doubt this is true as a semijoin's qual can actually reference its
> RHS.  In this case the assertion failure happens because there is PHV in
> the join's qual.

Yeah, the possibility of a PHV in the qual refutes that argument.
So we need to make the test honestly, as in the other arms of that
switch.  Will fix.

			regards, tom lane