Richard Guo <guofenglinux@gmail.com> writes:
> On Mon, Nov 6, 2023 at 10:39 PM PG Bug reporting form <
> noreply@postgresql.org> wrote:
>> ERROR: wrong varnullingrels (b) (expected (b 3)) for Var 2/2
> It seems that when we optimize field selection from a whole-row Var into
> a simple Var while simplifying functions, we fail to propagate the
> nullingrels into the new Var.
Yup, good catch! Fix pushed with a little editorializing on the test
case (mainly to try to ensure cross-platform stability of its plan).
> Attached is a hotfix for this error. But I'm wondering if there are
> other similar cases where we have mismatched nullingrels that we haven't
> discovered yet. Any thoughts?
It's worrisome I agree. I looked through the other calls of makeVar()
and didn't find any that seemed wrong. (There are a lot of them that
are concerned with cases like manufacturing rowmark Vars, which I
think are OK because we don't support FOR UPDATE on nullable rels.)
Still, I wouldn't be totally surprised if we find a few more.
regards, tom lane