1 files changed, 30 insertions, 9 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 36997be5889..c5df505d491 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -2532,16 +2532,37 @@ replace_nestloop_params_mutator(Node *node, PlannerInfo *root)
 		Assert(phv->phlevelsup == 0);
 
 		/*
-		 * If not to be replaced, just return the PlaceHolderVar unmodified.
-		 * We use bms_overlap as a cheap/quick test to see if the PHV might be
-		 * evaluated in the outer rels, and then grab its PlaceHolderInfo to
-		 * tell for sure.
+		 * Check whether we need to replace the PHV.  We use bms_overlap as a
+		 * cheap/quick test to see if the PHV might be evaluated in the outer
+		 * rels, and then grab its PlaceHolderInfo to tell for sure.
 		 */
-		if (!bms_overlap(phv->phrels, root->curOuterRels))
-			return node;
-		if (!bms_is_subset(find_placeholder_info(root, phv, false)->ph_eval_at,
-						   root->curOuterRels))
-			return node;
+		if (!bms_overlap(phv->phrels, root->curOuterRels) ||
+		  !bms_is_subset(find_placeholder_info(root, phv, false)->ph_eval_at,
+						 root->curOuterRels))
+		{
+			/*
+			 * We can't replace the whole PHV, but we might still need to
+			 * replace Vars or PHVs within its expression, in case it ends up
+			 * actually getting evaluated here.  (It might get evaluated in
+			 * this plan node, or some child node; in the latter case we don't
+			 * really need to process the expression here, but we haven't got
+			 * enough info to tell if that's the case.)  Flat-copy the PHV
+			 * node and then recurse on its expression.
+			 *
+			 * Note that after doing this, we might have different
+			 * representations of the contents of the same PHV in different
+			 * parts of the plan tree.  This is OK because equal() will just
+			 * match on phid/phlevelsup, so setrefs.c will still recognize an
+			 * upper-level reference to a lower-level copy of the same PHV.
+			 */
+			PlaceHolderVar *newphv = makeNode(PlaceHolderVar);
+
+			memcpy(newphv, phv, sizeof(PlaceHolderVar));
+			newphv->phexpr = (Expr *)
+				replace_nestloop_params_mutator((Node *) phv->phexpr,
+												root);
+			return (Node *) newphv;
+		}
 		/* Create a Param representing the PlaceHolderVar */
 		param = assign_nestloop_param_placeholdervar(root, phv);
 		/* Is this param already listed in root->curOuterParams? */