Add relkind checks to certain contrib modules

The contrib extensions pageinspect, pg_visibility and pgstattuple only
work against regular relations which have storage.  They don't work
against foreign tables, partitioned (parent) tables, views, et al.

Add checks to the user-callable functions to return a useful error
message to the user if they mistakenly pass an invalid relation to a
function which doesn't accept that kind of relation.

In passing, improve some of the existing checks to use ereport() instead
of elog(), add a function to consolidate common checks where
appropriate, and add some regression tests.

Author: Amit Langote, with various changes by me
Reviewed by: Michael Paquier and Corey Huinker
Discussion: https://postgr.es/m/ab91fd9d-4751-ee77-c87b-4dd704c1e59c@lab.ntt.co.jp

3 files changed, 23 insertions, 0 deletions

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 13964cd878..9eaeda3a27 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -71,3 +71,12 @@ SELECT * FROM fsm_page_contents(get_raw_page('test1', 'fsm', 0));
 (1 row)
 
 DROP TABLE test1;
+-- check that using any of these functions with a partitioned table would fail
+create table test_partitioned (a int) partition by range (a);
+select get_raw_page('test_partitioned', 0); -- error about partitioned table
+ERROR:  cannot get raw page from partitioned table "test_partitioned"
+-- a regular table which is a member of a partition set should work though
+create table test_part1 partition of test_partitioned for values from ( 1 ) to (100);
+select get_raw_page('test_part1', 0); -- get farther and error about empty table
+ERROR:  block number 0 is out of range for relation "test_part1"
+drop table test_partitioned;
diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index 102f360c6f..1ccc3ff320 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -123,6 +123,11 @@ get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot get raw page from foreign table \"%s\"",
 						RelationGetRelationName(rel))));
+	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("cannot get raw page from partitioned table \"%s\"",
+						RelationGetRelationName(rel))));
 
 	/*
 	 * Reject attempts to read non-local temporary relations; we would be
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 97eef9829a..6b2e6b79a2 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -28,3 +28,12 @@ SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bi
 SELECT * FROM fsm_page_contents(get_raw_page('test1', 'fsm', 0));
 
 DROP TABLE test1;
+
+-- check that using any of these functions with a partitioned table would fail
+create table test_partitioned (a int) partition by range (a);
+select get_raw_page('test_partitioned', 0); -- error about partitioned table
+
+-- a regular table which is a member of a partition set should work though
+create table test_part1 partition of test_partitioned for values from ( 1 ) to (100);
+select get_raw_page('test_part1', 0); -- get farther and error about empty table
+drop table test_partitioned;