diff --git a/src/backend/utils/adt/partitionfuncs.c b/src/backend/utils/adt/partitionfuncs.c
index 78dd2b542b..6fb4f6bc50 100644
--- a/src/backend/utils/adt/partitionfuncs.c
+++ b/src/backend/utils/adt/partitionfuncs.c
@@ -23,6 +23,7 @@
 #include "funcapi.h"
 #include "utils/fmgrprotos.h"
 #include "utils/lsyscache.h"
+#include "utils/syscache.h"
 
 
 /*
@@ -42,16 +43,16 @@ pg_partition_tree(PG_FUNCTION_ARGS)
 	FuncCallContext *funcctx;
 	ListCell  **next;
 
-	/* Only allow relation types that can appear in partition trees. */
+	if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(rootrelid)))
+		PG_RETURN_NULL();
+
+	/* Return NULL for relation types that cannot appear in partition trees */
 	if (relkind != RELKIND_RELATION &&
 		relkind != RELKIND_FOREIGN_TABLE &&
 		relkind != RELKIND_INDEX &&
 		relkind != RELKIND_PARTITIONED_TABLE &&
 		relkind != RELKIND_PARTITIONED_INDEX)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table, a foreign table, or an index",
-						get_rel_name(rootrelid))));
+		PG_RETURN_NULL();
 
 	/* stuff done only on the first call of the function */
 	if (SRF_IS_FIRSTCALL())
diff --git a/src/test/regress/expected/partition_info.out b/src/test/regress/expected/partition_info.out
index 6b116125e6..202d820827 100644
--- a/src/test/regress/expected/partition_info.out
+++ b/src/test/regress/expected/partition_info.out
@@ -6,6 +6,12 @@ SELECT * FROM pg_partition_tree(NULL);
 -------+-------------+--------+-------
 (0 rows)
 
+SELECT * FROM pg_partition_tree(0);
+ relid | parentrelid | isleaf | level 
+-------+-------------+--------+-------
+       |             |        |      
+(1 row)
+
 -- Test table partition trees
 CREATE TABLE ptif_test (a int, b int) PARTITION BY range (a);
 CREATE TABLE ptif_test0 PARTITION OF ptif_test
@@ -107,8 +113,16 @@ DROP TABLE ptif_normal_table;
 CREATE VIEW ptif_test_view AS SELECT 1;
 CREATE MATERIALIZED VIEW ptif_test_matview AS SELECT 1;
 SELECT * FROM pg_partition_tree('ptif_test_view');
-ERROR:  "ptif_test_view" is not a table, a foreign table, or an index
+ relid | parentrelid | isleaf | level 
+-------+-------------+--------+-------
+       |             |        |      
+(1 row)
+
 SELECT * FROM pg_partition_tree('ptif_test_matview');
-ERROR:  "ptif_test_matview" is not a table, a foreign table, or an index
+ relid | parentrelid | isleaf | level 
+-------+-------------+--------+-------
+       |             |        |      
+(1 row)
+
 DROP VIEW ptif_test_view;
 DROP MATERIALIZED VIEW ptif_test_matview;
diff --git a/src/test/regress/sql/partition_info.sql b/src/test/regress/sql/partition_info.sql
index 5a76f22b05..9b55a7fe5c 100644
--- a/src/test/regress/sql/partition_info.sql
+++ b/src/test/regress/sql/partition_info.sql
@@ -2,6 +2,7 @@
 -- Tests for pg_partition_tree
 --
 SELECT * FROM pg_partition_tree(NULL);
+SELECT * FROM pg_partition_tree(0);
 
 -- Test table partition trees
 CREATE TABLE ptif_test (a int, b int) PARTITION BY range (a);