| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | David Rowley <dgrowleyml(at)gmail(dot)com> |
| Cc: | feasiblechart(at)gmail(dot)com, pgsql-bugs(at)lists(dot)postgresql(dot)org |
| Subject: | Re: BUG #19742: `INTERSECT` under a `UNION ALL` with an empty arm fails with "could not find pathkey item t" |
| Date: | 2026-10-04 17:01:39 |
| Message-ID: | 401041.1791133299@sss.pgh.pa.us |
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| Thread: | |
| Lists: | pgsql-bugs |
I wrote:
> My own thoughts were along the lines of "don't ever assign pathkeys to
> an AppendPath"; not sure if that's equivalent to your first idea.
Concretely, the attached fixes the given test case. There are other
calls to create_append_path in prepunion.c, and I think they may
all need to do likewise, but I didn't analyze them.
It'd be nominally cleaner to add a flag to create_append_path telling
it whether it's allowed to override the given pathkeys. I didn't do
that here because it seems like this is a localized problem that
should eventually be fixed inside prepunion.c, but there's room to
argue differently.
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| wip-fix-bad-pathkeys-for-UNION-append.patch | text/x-diff | 1.1 KB |
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