From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <dgrowleyml@gmail.com>
cc: xinwen@stu.scu.edu.cn, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17826: An assert failed in /src/backend/optimizer/util/var.c
In-reply-to: 
 <CAApHDvoGAu9rY4iO0R+DZVxPck_M3015WUL_34XOhi9ygxYfnA@mail.gmail.com>
References: <17826-7d8750952f19a5f5@postgresql.org>
 <402866.1678378153@sss.pgh.pa.us>
 <CAApHDvoGAu9rY4iO0R+DZVxPck_M3015WUL_34XOhi9ygxYfnA@mail.gmail.com>
Comments: In-reply-to David Rowley <dgrowleyml@gmail.com>
	message dated "Sat, 11 Mar 2023 19:35:07 +1300"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <1229466.1678555436.1@sss.pgh.pa.us>
Date: Sat, 11 Mar 2023 12:23:56 -0500
Message-ID: <1229467.1678555436@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/1229467.1678555436%40sss.pgh.pa.us>
Precedence: bulk

David Rowley <dgrowleyml@gmail.com> writes:
> On Fri, 10 Mar 2023 at 05:09, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> How is this even a little bit sane?

> I don't think it is.  I've not looked in detail yet, but I think we
> might be able to do something in check_output_expressions() so that we
> track the targetIsInAllPartitionLists() separately.  Maybe
> unsafeColumns[] needs to become an enum type that has UNSAFE, SAFE,
> WINDOW_RUNCONDITION_ONLY and then change things so we never make a
> runCondition when the qual is UNSAFE.

> Anyway, I'll give it more thought and aim to come up with a patch
> early next week.

Why can't we simply *remove* all this logic from subquery pushdown?

I would expect that what happens in useful cases is that we push down
the (safe) qual and then during planning of the subquery we see a WHERE
clause matching the window run condition and work with that.  So this
all seems redundant, quite aside from being faulty.

			regards, tom lane