pageinspect: Fix failure with hash_bitmap_info() for partitioned indexes

This function reads directly a page from a relation, relying on
index_open() to open the index to read from.  Unfortunately, this would
crash when using partitioned indexes, as these can be opened with
index_open() but they have no physical pages.

Alexander has fixed the module, while I have written the test.

Author: Alexander Lakhin, Michael Paquier
Discussion: https://postgr.es/m/18246-f4d9ff7cb3af77e6@postgresql.org
Backpatch-through: 12

1 files changed, 5 insertions, 0 deletions

diff --git a/contrib/pageinspect/sql/hash.sql b/contrib/pageinspect/sql/hash.sql
index 320fb9fa9f1..e4b9e975f8a 100644
--- a/contrib/pageinspect/sql/hash.sql
+++ b/contrib/pageinspect/sql/hash.sql
@@ -2,6 +2,9 @@ CREATE TABLE test_hash (a int, b text);
 INSERT INTO test_hash VALUES (1, 'one');
 CREATE INDEX test_hash_a_idx ON test_hash USING hash (a);
 
+CREATE TABLE test_hash_part (a int, b int) PARTITION BY RANGE (a);
+CREATE INDEX test_hash_part_idx ON test_hash_part USING hash(b);
+
 \x
 
 SELECT hash_page_type(get_raw_page('test_hash_a_idx', 0));
@@ -21,6 +24,7 @@ SELECT * FROM hash_bitmap_info('test_hash_a_idx', 3);
 SELECT * FROM hash_bitmap_info('test_hash_a_idx', 4);
 SELECT * FROM hash_bitmap_info('test_hash_a_idx', 5);
 SELECT * FROM hash_bitmap_info('test_hash_a_idx', 6);
+SELECT * FROM hash_bitmap_info('test_hash_part_idx', 1); -- error
 
 
 SELECT magic, version, ntuples, bsize, bmsize, bmshift, maxbucket, highmask,
@@ -106,3 +110,4 @@ SELECT hash_page_stats(decode(repeat('00', :block_size), 'hex'));
 SELECT hash_page_type(decode(repeat('00', :block_size), 'hex'));
 
 DROP TABLE test_hash;
+DROP TABLE test_hash_part;