diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 4fb6ec60d4..ffd946a445 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -2643,20 +2643,22 @@ RelationClearRelation(Relation relation, bool rebuild)
 			 * no PartitionDirectory with a pointer to the old entry.
 			 *
 			 * To avoid leaking memory, we've got to make sure that the next
-			 * time rd_pdoldcxt is destroyed, the old context will be freed.
-			 * If rd_pdoldcxt is NULL, we can just make it point to the
-			 * old descriptor's context; otherwise, we make this context of
-			 * the previous one.
+			 * time rd_pdoldcxt is destroyed, all the old contexts will be
+			 * freed.  So, if there's already an older context present, make
+			 * this the parent of the previous one.
 			 *
 			 * Note that newrel and relation have already been swapped, so the
-			 * "old" partition descriptor is actually the one hanging off of
-			 * newrel.
+			 * "old" partition descriptor and the associated "old" context are
+			 * actually those that are hanging off of newrel.
 			 */
-			if (relation->rd_pdoldcxt == NULL)
-				relation->rd_pdoldcxt = newrel->rd_pdcxt;
-			else
-				MemoryContextSetParent(newrel->rd_pdcxt,
+			Assert(relation->rd_pdoldcxt == NULL);
+			relation->rd_pdoldcxt = newrel->rd_pdcxt;
+			if (newrel->rd_pdoldcxt)
+			{
+				MemoryContextSetParent(newrel->rd_pdoldcxt,
 									   relation->rd_pdoldcxt);
+				newrel->rd_pdoldcxt = NULL;
+			}
 			newrel->rd_partdesc = NULL;
 			newrel->rd_pdcxt = NULL;
 		}