From 36f5594c0fe694600c07c803324b51fcfbea4079 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 9 Nov 2023 15:46:16 -0500 Subject: Fix computation of varnullingrels when const-folding field selection. We can simplify FieldSelect on a whole-row Var into a plain Var for the selected field. However, we should copy the whole-row Var's varnullingrels when we do so, because the new Var is clearly nullable by exactly the same rels as the original. Failure to do this led to errors like "wrong varnullingrels (b) (expected (b 3)) for Var 2/2". Richard Guo, per bug #18184 from Marian Krucina. Back-patch to v16 where varnullingrels was introduced. Discussion: https://postgr.es/m/18184-5868dd258782058e@postgresql.org --- src/backend/optimizer/util/clauses.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) (limited to 'src/backend') diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index da258968b8c..948c2bf06db 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -3296,12 +3296,19 @@ eval_const_expressions_mutator(Node *node, fselect->resulttype, fselect->resulttypmod, fselect->resultcollid)) - return (Node *) makeVar(((Var *) arg)->varno, - fselect->fieldnum, - fselect->resulttype, - fselect->resulttypmod, - fselect->resultcollid, - ((Var *) arg)->varlevelsup); + { + Var *newvar; + + newvar = makeVar(((Var *) arg)->varno, + fselect->fieldnum, + fselect->resulttype, + fselect->resulttypmod, + fselect->resultcollid, + ((Var *) arg)->varlevelsup); + /* New Var is nullable by same rels as the old one */ + newvar->varnullingrels = ((Var *) arg)->varnullingrels; + return (Node *) newvar; + } } if (arg && IsA(arg, RowExpr)) { -- cgit v1.2.3