postgresql/contrib/pg_visibility/sql/pg_visibility.sql
Andres Freund 408209d6a9 Avoid edge case in pg_visibility test with small shared_buffers
Since 82a4edabd2 we can bulk extend relations. The bulk relation extension
logic has a heuristic component. Normally the heurstic does not trigger in the
occasionally-failing test case, as the relation is only extended once. But
with very small shared_buffers the limits for the number of buffers pinned at
once prevent the extension from happening at once. With the second "bulk"
extension, the heuristic kicks in, and the relation ends up one block bigger.
That's ok from a correctness perspective, but changes the results of the test
query due to one additional block.

We discussed a few more expansive fixes, but for now have decided to avoid
this by making the table a bit smaller.

Author: Heikki Linnakangas <hlinnaka@iki.fi>
Reported-by:
Discussion: https://postgr.es/m/29c74104-210b-ef39-2522-27a6aa7a704f@iki.fi
Discussion: https://postgr.es/m/20230916000011.2ugpkkkp7bpp4cfh@awork3.anarazel.de
Backpatch: 16-, where the new relation extension logic was added
2024-03-25 20:20:34 -07:00

177 lines
5.4 KiB
PL/PgSQL

CREATE EXTENSION pg_visibility;
--
-- recently-dropped table
--
\set VERBOSITY sqlstate
BEGIN;
CREATE TABLE droppedtest (c int);
SELECT 'droppedtest'::regclass::oid AS oid \gset
SAVEPOINT q; DROP TABLE droppedtest; RELEASE q;
SAVEPOINT q; SELECT * FROM pg_visibility_map(:oid); ROLLBACK TO q;
-- ERROR: could not open relation with OID 16xxx
SAVEPOINT q; SELECT 1; ROLLBACK TO q;
SAVEPOINT q; SELECT 1; ROLLBACK TO q;
SELECT pg_relation_size(:oid), pg_relation_filepath(:oid),
has_table_privilege(:oid, 'SELECT');
SELECT * FROM pg_visibility_map(:oid);
-- ERROR: could not open relation with OID 16xxx
ROLLBACK;
\set VERBOSITY default
--
-- check that using the module's functions with unsupported relations will fail
--
-- partitioned tables (the parent ones) don't have visibility maps
create table test_partitioned (a int) partition by list (a);
-- these should all fail
select pg_visibility('test_partitioned', 0);
select pg_visibility_map('test_partitioned');
select pg_visibility_map_summary('test_partitioned');
select pg_check_frozen('test_partitioned');
select pg_truncate_visibility_map('test_partitioned');
create table test_partition partition of test_partitioned for values in (1);
create index test_index on test_partition (a);
-- indexes do not, so these all fail
select pg_visibility('test_index', 0);
select pg_visibility_map('test_index');
select pg_visibility_map_summary('test_index');
select pg_check_frozen('test_index');
select pg_truncate_visibility_map('test_index');
create view test_view as select 1;
-- views do not have VMs, so these all fail
select pg_visibility('test_view', 0);
select pg_visibility_map('test_view');
select pg_visibility_map_summary('test_view');
select pg_check_frozen('test_view');
select pg_truncate_visibility_map('test_view');
create sequence test_sequence;
-- sequences do not have VMs, so these all fail
select pg_visibility('test_sequence', 0);
select pg_visibility_map('test_sequence');
select pg_visibility_map_summary('test_sequence');
select pg_check_frozen('test_sequence');
select pg_truncate_visibility_map('test_sequence');
create foreign data wrapper dummy;
create server dummy_server foreign data wrapper dummy;
create foreign table test_foreign_table () server dummy_server;
-- foreign tables do not have VMs, so these all fail
select pg_visibility('test_foreign_table', 0);
select pg_visibility_map('test_foreign_table');
select pg_visibility_map_summary('test_foreign_table');
select pg_check_frozen('test_foreign_table');
select pg_truncate_visibility_map('test_foreign_table');
-- check some of the allowed relkinds
create table regular_table (a int, b text);
alter table regular_table alter column b set storage external;
insert into regular_table values (1, repeat('one', 1000)), (2, repeat('two', 1000));
vacuum (disable_page_skipping) regular_table;
select count(*) > 0 from pg_visibility('regular_table');
select count(*) > 0 from pg_visibility((select reltoastrelid from pg_class where relname = 'regular_table'));
truncate regular_table;
select count(*) > 0 from pg_visibility('regular_table');
select count(*) > 0 from pg_visibility((select reltoastrelid from pg_class where relname = 'regular_table'));
create materialized view matview_visibility_test as select * from regular_table;
vacuum (disable_page_skipping) matview_visibility_test;
select count(*) > 0 from pg_visibility('matview_visibility_test');
insert into regular_table values (1), (2);
refresh materialized view matview_visibility_test;
select count(*) > 0 from pg_visibility('matview_visibility_test');
-- regular tables which are part of a partition *do* have visibility maps
insert into test_partition values (1);
vacuum (disable_page_skipping) test_partition;
select count(*) > 0 from pg_visibility('test_partition', 0);
select count(*) > 0 from pg_visibility_map('test_partition');
select count(*) > 0 from pg_visibility_map_summary('test_partition');
select * from pg_check_frozen('test_partition'); -- hopefully none
select pg_truncate_visibility_map('test_partition');
-- test copy freeze
create table copyfreeze (a int, b char(1500));
-- load all rows via COPY FREEZE and ensure that all pages are set all-visible
-- and all-frozen.
begin;
truncate copyfreeze;
copy copyfreeze from stdin freeze;
1 '1'
2 '2'
3 '3'
4 '4'
5 '5'
6 '6'
\.
commit;
select * from pg_visibility_map('copyfreeze');
select * from pg_check_frozen('copyfreeze');
-- load half the rows via regular COPY and rest via COPY FREEZE. The pages
-- which are touched by regular COPY must not be set all-visible/all-frozen. On
-- the other hand, pages allocated by COPY FREEZE should be marked
-- all-frozen/all-visible.
begin;
truncate copyfreeze;
copy copyfreeze from stdin;
1 '1'
2 '2'
3 '3'
4 '4'
5 '5'
6 '6'
\.
copy copyfreeze from stdin freeze;
7 '7'
8 '8'
9 '9'
10 '10'
11 '11'
12 '12'
\.
commit;
select * from pg_visibility_map('copyfreeze');
select * from pg_check_frozen('copyfreeze');
-- Try a mix of regular COPY and COPY FREEZE.
begin;
truncate copyfreeze;
copy copyfreeze from stdin freeze;
1 '1'
2 '2'
3 '3'
4 '4'
5 '5'
\.
copy copyfreeze from stdin;
6 '6'
\.
copy copyfreeze from stdin freeze;
7 '7'
8 '8'
9 '9'
10 '10'
11 '11'
12 '12'
\.
commit;
select * from pg_visibility_map('copyfreeze');
select * from pg_check_frozen('copyfreeze');
-- cleanup
drop table test_partitioned;
drop view test_view;
drop sequence test_sequence;
drop foreign table test_foreign_table;
drop server dummy_server;
drop foreign data wrapper dummy;
drop materialized view matview_visibility_test;
drop table regular_table;
drop table copyfreeze;