diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 2bd069d889..9a631a9192 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -1791,6 +1791,9 @@ adjust_partition_colnos_using_map(List *colnos, AttrMap *attrMap)
  *		Initialize data structure needed for run-time partition pruning and
  *		do initial pruning if needed
  *
+ * 'root_parent_relids' identifies the relation to which both the parent plan
+ * and the PartitionPruneInfo given by 'part_prune_index' belong.
+ *
  * On return, *initially_valid_subplans is assigned the set of indexes of
  * child subplans that must be initialized along with the parent plan node.
  * Initial pruning is performed here if needed and in that case only the
@@ -1804,6 +1807,7 @@ PartitionPruneState *
 ExecInitPartitionPruning(PlanState *planstate,
 						 int n_total_subplans,
 						 int part_prune_index,
+						 Bitmapset *root_parent_relids,
 						 Bitmapset **initially_valid_subplans)
 {
 	PartitionPruneState *prunestate;
@@ -1811,6 +1815,14 @@ ExecInitPartitionPruning(PlanState *planstate,
 	PartitionPruneInfo *pruneinfo = list_nth(estate->es_part_prune_infos,
 											 part_prune_index);
 
+	/* Sanity: part_prune_index gives the correct PartitionPruneInfo. */
+	if (!bms_equal(root_parent_relids, pruneinfo->root_parent_relids))
+		elog(ERROR, "wrong relids (%s) found in PartitionPruneInfo at part_prune_index=%u which has root_parent_relids=%s",
+			 bmsToString(root_parent_relids),
+			 part_prune_index,
+			 bmsToString(pruneinfo->root_parent_relids));
+
+
 	/* We may need an expression context to evaluate partition exprs */
 	ExecAssignExprContext(estate, planstate);
 
diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
index c6f86a6510..99830198bd 100644
--- a/src/backend/executor/nodeAppend.c
+++ b/src/backend/executor/nodeAppend.c
@@ -146,6 +146,7 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 		prunestate = ExecInitPartitionPruning(&appendstate->ps,
 											  list_length(node->appendplans),
 											  node->part_prune_index,
+											  node->apprelids,
 											  &validsubplans);
 		appendstate->as_prune_state = prunestate;
 		nplans = bms_num_members(validsubplans);
diff --git a/src/backend/executor/nodeMergeAppend.c b/src/backend/executor/nodeMergeAppend.c
index 8d35860c30..f370f9f287 100644
--- a/src/backend/executor/nodeMergeAppend.c
+++ b/src/backend/executor/nodeMergeAppend.c
@@ -94,6 +94,7 @@ ExecInitMergeAppend(MergeAppend *node, EState *estate, int eflags)
 		prunestate = ExecInitPartitionPruning(&mergestate->ps,
 											  list_length(node->mergeplans),
 											  node->part_prune_index,
+											  node->apprelids,
 											  &validsubplans);
 		mergestate->ms_prune_state = prunestate;
 		nplans = bms_num_members(validsubplans);
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 720f20f563..e67f0e3509 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -354,6 +354,8 @@ set_plan_references(PlannerInfo *root, Plan *plan)
 		PartitionPruneInfo *pruneinfo = lfirst(lc);
 		ListCell  *l;
 
+		pruneinfo->root_parent_relids =
+			offset_relid_set(pruneinfo->root_parent_relids, rtoffset);
 		foreach(l, pruneinfo->prune_infos)
 		{
 			List	   *prune_infos = lfirst(l);
diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index 6565b6ed01..d48f6784c1 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -340,6 +340,7 @@ make_partition_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
 
 	/* Else build the result data structure */
 	pruneinfo = makeNode(PartitionPruneInfo);
+	pruneinfo->root_parent_relids = parentrel->relids;
 	pruneinfo->prune_infos = prunerelinfos;
 
 	/*
diff --git a/src/include/executor/execPartition.h b/src/include/executor/execPartition.h
index bf962af7af..17fabc18c9 100644
--- a/src/include/executor/execPartition.h
+++ b/src/include/executor/execPartition.h
@@ -124,6 +124,7 @@ typedef struct PartitionPruneState
 extern PartitionPruneState *ExecInitPartitionPruning(PlanState *planstate,
 													 int n_total_subplans,
 													 int part_prune_index,
+													 Bitmapset *root_parent_relids,
 													 Bitmapset **initially_valid_subplans);
 extern Bitmapset *ExecFindMatchingSubPlans(PartitionPruneState *prunestate,
 										   bool initial_prune);
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 2e132afc5a..b2d6f8fb6e 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -1407,6 +1407,8 @@ typedef struct PlanRowMark
  * Then, since an Append-type node could have multiple partitioning
  * hierarchies among its children, we have an unordered List of those Lists.
  *
+ * root_parent_relids	RelOptInfo.relids of the relation to which the parent
+ *						plan node and this PartitionPruneInfo node belong
  * prune_infos			List of Lists containing PartitionedRelPruneInfo nodes,
  *						one sublist per run-time-prunable partition hierarchy
  *						appearing in the parent plan node's subplans.
@@ -1419,6 +1421,7 @@ typedef struct PartitionPruneInfo
 	pg_node_attr(no_equal)
 
 	NodeTag		type;
+	Bitmapset  *root_parent_relids;
 	List	   *prune_infos;
 	Bitmapset  *other_subplans;
 } PartitionPruneInfo;