1 files changed, 58 insertions, 0 deletions

diff --git a/src/backend/optimizer/util/placeholder.c b/src/backend/optimizer/util/placeholder.c
index 970542dde5b..3343521b971 100644
--- a/src/backend/optimizer/util/placeholder.c
+++ b/src/backend/optimizer/util/placeholder.c
@@ -20,6 +20,7 @@
 #include "optimizer/pathnode.h"
 #include "optimizer/placeholder.h"
 #include "optimizer/planmain.h"
+#include "optimizer/prep.h"
 #include "optimizer/var.h"
 #include "utils/lsyscache.h"
 
@@ -414,6 +415,10 @@ add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel,
 	Relids		relids = joinrel->relids;
 	ListCell   *lc;
 
+	/* This function is called only on the parent relations. */
+	Assert(!IS_OTHER_REL(joinrel) && !IS_OTHER_REL(outer_rel) &&
+		   !IS_OTHER_REL(inner_rel));
+
 	foreach(lc, root->placeholder_list)
 	{
 		PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
@@ -459,3 +464,56 @@ add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel,
 		}
 	}
 }
+
+/*
+ * add_placeholders_to_child_joinrel
+ *		Translate the PHVs in parent's targetlist and add them to the child's
+ *		targetlist. Also adjust the cost
+ */
+void
+add_placeholders_to_child_joinrel(PlannerInfo *root, RelOptInfo *childrel,
+								  RelOptInfo *parentrel)
+{
+	ListCell   *lc;
+	AppendRelInfo **appinfos;
+	int			nappinfos;
+
+	Assert(IS_JOIN_REL(childrel) && IS_JOIN_REL(parentrel));
+	Assert(IS_OTHER_REL(childrel));
+
+	/* Nothing to do if no PHVs. */
+	if (root->placeholder_list == NIL)
+		return;
+
+	appinfos = find_appinfos_by_relids(root, childrel->relids, &nappinfos);
+	foreach(lc, parentrel->reltarget->exprs)
+	{
+		PlaceHolderVar *phv = lfirst(lc);
+
+		if (IsA(phv, PlaceHolderVar))
+		{
+			/*
+			 * In case the placeholder Var refers to any of the parent
+			 * relations, translate it to refer to the corresponding child.
+			 */
+			if (bms_overlap(phv->phrels, parentrel->relids) &&
+				childrel->reloptkind == RELOPT_OTHER_JOINREL)
+			{
+				phv = (PlaceHolderVar *) adjust_appendrel_attrs(root,
+																(Node *) phv,
+																nappinfos,
+																appinfos);
+			}
+
+			childrel->reltarget->exprs = lappend(childrel->reltarget->exprs,
+												 phv);
+		}
+	}
+
+	/* Adjust the cost and width of child targetlist. */
+	childrel->reltarget->cost.startup = parentrel->reltarget->cost.startup;
+	childrel->reltarget->cost.per_tuple = parentrel->reltarget->cost.per_tuple;
+	childrel->reltarget->width = parentrel->reltarget->width;
+
+	pfree(appinfos);
+}