diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0497332e9d..a049234390 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -1769,7 +1769,8 @@ heap_drop_with_catalog(Oid relid)
 	 * could attempt to access the just-dropped relation as its partition. We
 	 * must therefore take a table lock strong enough to prevent all queries
 	 * on the table from proceeding until we commit and send out a
-	 * shared-cache-inval notice that will make them update their index lists.
+	 * shared-cache-inval notice that will make them update their partition
+	 * descriptors.
 	 */
 	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
 	if (!HeapTupleIsValid(tuple))
@@ -3247,6 +3248,9 @@ RemovePartitionKeyByRelId(Oid relid)
  *		Update pg_class tuple of rel to store the partition bound and set
  *		relispartition to true
  *
+ * If this is the default partition, also update the default partition OID in
+ * pg_partitioned_table.
+ *
  * Also, invalidate the parent's relcache, so that the next rebuild will load
  * the new partition's info into its partition descriptor.  If there is a
  * default partition, we must invalidate its relcache entry as well.
@@ -3298,7 +3302,17 @@ StorePartitionBound(Relation rel, Relation parent, PartitionBoundSpec *bound)
 	heap_freetuple(newtuple);
 	heap_close(classRel, RowExclusiveLock);
 
-	/* Make update visible */
+	/*
+	 * If we're storing bounds for the default partition, update
+	 * pg_partitioned_table too.  This must happen before CCI, to avoid risk
+	 * of constructing a partition descriptor lacking the default partition
+	 * OID.
+	 */
+	if (bound->is_default)
+		update_default_partition_oid(RelationGetRelid(parent),
+									 RelationGetRelid(rel));
+
+	/* Make these updates visible */
 	CommandCounterIncrement();
 
 	/*
diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c
index 786c05df73..53855f5088 100644
--- a/src/backend/catalog/partition.c
+++ b/src/backend/catalog/partition.c
@@ -227,13 +227,6 @@ RelationBuildPartitionDesc(Relation rel)
 	/* Range partitioning specific */
 	PartitionRangeBound **rbounds = NULL;
 
-	/*
-	 * The following could happen in situations where rel has a pg_class entry
-	 * but not the pg_partitioned_table entry yet.
-	 */
-	if (key == NULL)
-		return;
-
 	/* Get partition oids from pg_inherits */
 	inhoids = find_inheritance_children(RelationGetRelid(rel), NoLock);
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8f83aa4675..c4cf0abadc 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -859,10 +859,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 		/* Update the pg_class entry. */
 		StorePartitionBound(rel, parent, bound);
 
-		/* Update the default partition oid */
-		if (bound->is_default)
-			update_default_partition_oid(RelationGetRelid(parent), relationId);
-
 		heap_close(parent, NoLock);
 	}
 
@@ -14020,11 +14016,6 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	/* OK to create inheritance.  Rest of the checks performed there */
 	CreateInheritance(attachrel, rel);
 
-	/* Update the default partition oid */
-	if (cmd->bound->is_default)
-		update_default_partition_oid(RelationGetRelid(rel),
-									 RelationGetRelid(attachrel));
-
 	/*
 	 * Check that the new partition's bound is valid and does not overlap any
 	 * of existing partitions of the parent - note that it does not return on
-- 
2.11.0