Re: ERROR: PlaceHolderVar found where not expected

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>, Tomas Vondra <tomas.vondra@enterprisedb.com>
Date: 2023-03-14T03:32:31Z
Lists: pgsql-bugs
Richard Guo <guofenglinux@gmail.com> writes:
> I came across an ERROR as $subject with query below.
> ...
> This is due to that we use 0 flags for pull_var_clause in
> dependency_is_compatible_expression, assuming that the 'clause_expr'
> cannot contain Aggrefs, WindowFuncs or PlaceHolderVars.  This should be
> an oversight as we can see that it's possible to find PHVs here.

Nice catch.

> But I'm not sure if Aggrefs and WindowFuncs are possible to be found
> here.

WindowFuncs should be disallowed in qual clauses, so I think it's okay
to leave those flags out.  An Aggref could occur in a HAVING qual though.
I'm not sure if this code could get applied to HAVING ... but it's
not immediately clear that it can't.  I'd be inclined to add
PVC_RECURSE_AGGREGATES, as that seems more likely to be okay than not.

			regards, tom lane



Commits

  1. Remove unnecessary code in dependency_is_compatible_expression().