Richard Guo <[email protected]> 于2026年4月10日周五 22:39写道： > > On Fri, Apr 10, 2026 at 9:49 PM Tender Wang <[email protected]> wrote: > > Justin Pryzby <[email protected]> 于2026年4月10日周五 18:54写道： > > > CREATE VIEW x AS SELECT NULL::int[] > > > UNION ALL SELECT NULL::int[] > > > UNION ALL SELECT ARRAY[NULL::bigint]; > > > > > > SELECT FROM x; > > > ERROR: XX000: no relation entry for relid 0 > > Nice catch. It seems that we need at least three branches to > reproduce this, so that there's a nested UNION ALL whose output type > doesn't match the parent's expected type. At the outer branch maybe > we can use NULL::bigint[] instead to be a little simpler. > > SELECT NULL::int[] UNION ALL SELECT NULL::int[] UNION ALL SELECT > NULL::bigint[]; > ERROR: no relation entry for relid 0
Yes, add it to the test case.
>
> > I didn't think too much at now, a quick fix as below:
> > diff --git a/src/backend/utils/adt/selfuncs.c
> > b/src/backend/utils/adt/selfuncs.c
> > index 4160d2d6e24..ff93fc3ac8a 100644
> > --- a/src/backend/utils/adt/selfuncs.c
> > +++ b/src/backend/utils/adt/selfuncs.c
> > @@ -2265,6 +2265,9 @@ estimate_array_length(PlannerInfo *root, Node
> > *arrayexpr)
> > AttStatsSlot sslot;
> > double nelem = 0;
> >
> > + if (IsA(arrayexpr, Var) && ((Var *) arrayexpr)->varno == 0)
> > + return 10;
> > +
> > examine_variable(root, arrayexpr, 0, &vardata);
> > if (HeapTupleIsValid(vardata.statsTuple))
> > {
> >
> > Any thoughts?
>
> This looks like the right fix to me. We can use some comment here.
comments added.
Please see the attached patch.
--
Thanks,
Tender Wang
0001-Fix-no-relation-entry-for-relid-0-in-nested-UNION-AL.patch
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