pgstattuple: Fix failure with pgstathashindex() for partitioned indexes

michaelpq · michaelpq · commit a8dd62ef4959 · 2023-12-19T15:20:39.000+09:00
As coded, the function relied on index_open() when opening an index relation, allowing partitioned indexes to be processed by pgstathashindex(). This was leading to a "could not open file" error because partitioned indexes have no physical files, or to a crash with an assertion failure (like on HEAD). This issue is fixed by applying the same checks as the other stat functions for indexes, with a lookup at both RELKIND_INDEX and the index AM expected. Author: Alexander Lakhin Discussion: https://postgr.es/m/18246-f4d9ff7cb3af77e6@postgresql.org Backpatch-through: 12
diff --git a/contrib/pgstattuple/expected/pgstattuple.out b/contrib/pgstattuple/expected/pgstattuple.out
@@ -153,6 +153,7 @@ ERROR:  relation "test_hashidx" is not a GIN index
 -- check that using any of these functions with unsupported relations will fail
 create table test_partitioned (a int) partition by range (a);
 create index test_partitioned_index on test_partitioned(a);
+create index test_partitioned_hash_index on test_partitioned using hash(a);
 -- these should all fail
 select pgstattuple('test_partitioned');
 ERROR:  cannot get tuple-level statistics for relation "test_partitioned"
@@ -171,7 +172,9 @@ ERROR:  relation "test_partitioned" is not a btree index
 select pgstatginindex('test_partitioned');
 ERROR:  relation "test_partitioned" is not a GIN index
 select pgstathashindex('test_partitioned');
-ERROR:  "test_partitioned" is not an index
+ERROR:  relation "test_partitioned" is not a hash index
+select pgstathashindex('test_partitioned_hash_index');
+ERROR:  relation "test_partitioned_hash_index" is not a hash index
 create view test_view as select 1;
 -- these should all fail
 select pgstattuple('test_view');
@@ -188,7 +191,7 @@ ERROR:  relation "test_view" is not a btree index
 select pgstatginindex('test_view');
 ERROR:  relation "test_view" is not a GIN index
 select pgstathashindex('test_view');
-ERROR:  "test_view" is not an index
+ERROR:  relation "test_view" is not a hash index
 create foreign data wrapper dummy;
 create server dummy_server foreign data wrapper dummy;
 create foreign table test_foreign_table () server dummy_server;
@@ -207,7 +210,7 @@ ERROR:  relation "test_foreign_table" is not a btree index
 select pgstatginindex('test_foreign_table');
 ERROR:  relation "test_foreign_table" is not a GIN index
 select pgstathashindex('test_foreign_table');
-ERROR:  "test_foreign_table" is not an index
+ERROR:  relation "test_foreign_table" is not a hash index
 -- a partition of a partitioned table should work though
 create table test_partition partition of test_partitioned for values from (1) to (100);
 select pgstattuple('test_partition');
@@ -253,7 +256,7 @@ ERROR:  relation "test_partition" is not a btree index
 select pgstatginindex('test_partition');
 ERROR:  relation "test_partition" is not a GIN index
 select pgstathashindex('test_partition');
-ERROR:  "test_partition" is not an index
+ERROR:  relation "test_partition" is not a hash index
 -- an actual index of a partitioned table should work though
 create index test_partition_idx on test_partition(a);
 create index test_partition_hash_idx on test_partition using hash (a);
diff --git a/contrib/pgstattuple/pgstatindex.c b/contrib/pgstattuple/pgstatindex.c
@@ -600,10 +600,9 @@ pgstathashindex(PG_FUNCTION_ARGS)
 	float8		free_percent;
 	uint64		total_space;
 
-	rel = index_open(relid, AccessShareLock);
+	rel = relation_open(relid, AccessShareLock);
 
-	/* index_open() checks that it's an index */
-	if (!IS_HASH(rel))
+	if (!IS_INDEX(rel) || !IS_HASH(rel))
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("relation \"%s\" is not a hash index",
diff --git a/contrib/pgstattuple/sql/pgstattuple.sql b/contrib/pgstattuple/sql/pgstattuple.sql
@@ -65,6 +65,7 @@ select pgstatginindex('test_hashidx');
 -- check that using any of these functions with unsupported relations will fail
 create table test_partitioned (a int) partition by range (a);
 create index test_partitioned_index on test_partitioned(a);
+create index test_partitioned_hash_index on test_partitioned using hash(a);
 -- these should all fail
 select pgstattuple('test_partitioned');
 select pgstattuple('test_partitioned_index');
@@ -73,6 +74,7 @@ select pg_relpages('test_partitioned');
 select pgstatindex('test_partitioned');
 select pgstatginindex('test_partitioned');
 select pgstathashindex('test_partitioned');
+select pgstathashindex('test_partitioned_hash_index');
 
 create view test_view as select 1;
 -- these should all fail
