postgresql/contrib/pg_buffercache/expected/pg_buffercache.out
Fujii Masao b70d5672d0 pg_buffercache: restore rowtype verification in pg_buffercache_pages()
Commit 257c8231bf changed pg_buffercache_pages() to materialize its output
directly into a tuplestore. As a result, the function ended up trusting
a caller-supplied RECORD descriptors. That could lead to crashes
if the supplied row definition did not match the actual returned values,
for example by passing bool Datums to tuplestore_putvalues() with
an incompatible descriptor.

Fix this by constructing the correct tuple descriptor for
pg_buffercache_pages() and assigning it to
rsinfo->setDesc after InitMaterializedSRF(). This restores the executor's
tupledesc_match() verification, so incompatible caller-supplied
row definitions are rejected with an error, as before commit 257c8231bf.

Bug: #19508
Reported-by: Nikita Kalinin <n.kalinin@postgrespro.ru>
Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Reviewed-by: Ashutosh Sharma <ashu.coek88@gmail.com>
Discussion: https://postgr.es/m/19508-e5f188183279219b@postgresql.org
2026-06-10 12:32:59 +09:00

190 lines
5.8 KiB
Text

CREATE EXTENSION pg_buffercache;
select count(*) = (select setting::bigint
from pg_settings
where name = 'shared_buffers')
from pg_buffercache;
?column?
----------
t
(1 row)
-- For pg_buffercache_os_pages, we expect at least one entry for each buffer
select count(*) >= (select setting::bigint
from pg_settings
where name = 'shared_buffers')
from pg_buffercache_os_pages;
?column?
----------
t
(1 row)
select buffers_used + buffers_unused > 0,
buffers_dirty <= buffers_used,
buffers_pinned <= buffers_used
from pg_buffercache_summary();
?column? | ?column? | ?column?
----------+----------+----------
t | t | t
(1 row)
SELECT count(*) > 0 FROM pg_buffercache_usage_counts() WHERE buffers >= 0;
?column?
----------
t
(1 row)
-- Check that the functions / views can't be accessed by default. To avoid
-- having to create a dedicated user, use the pg_database_owner pseudo-role.
SET ROLE pg_database_owner;
SELECT * FROM pg_buffercache;
ERROR: permission denied for view pg_buffercache
SELECT * FROM pg_buffercache_os_pages;
ERROR: permission denied for view pg_buffercache_os_pages
SELECT * FROM pg_buffercache_pages() AS p (wrong int);
ERROR: permission denied for function pg_buffercache_pages
SELECT * FROM pg_buffercache_summary();
ERROR: permission denied for function pg_buffercache_summary
SELECT * FROM pg_buffercache_usage_counts();
ERROR: permission denied for function pg_buffercache_usage_counts
RESET role;
-- Check that pg_monitor is allowed to query view / function
SET ROLE pg_monitor;
SELECT count(*) > 0 FROM pg_buffercache;
?column?
----------
t
(1 row)
SELECT count(*) > 0 FROM pg_buffercache_os_pages;
?column?
----------
t
(1 row)
SELECT buffers_used + buffers_unused > 0 FROM pg_buffercache_summary();
?column?
----------
t
(1 row)
SELECT count(*) > 0 FROM pg_buffercache_usage_counts();
?column?
----------
t
(1 row)
SELECT *
FROM pg_buffercache_pages() AS p
(bufferid integer, relfilenode oid, reltablespace oid, reldatabase oid,
relforknumber smallint, relblocknumber bigint, isdirty text,
usagecount smallint)
LIMIT 1;
ERROR: function return row and query-specified return row do not match
DETAIL: Returned type boolean at ordinal position 7, but query expects text.
RESET role;
------
---- Test pg_buffercache_evict* and pg_buffercache_mark_dirty* functions
------
CREATE ROLE regress_buffercache_normal;
SET ROLE regress_buffercache_normal;
-- These should fail because they need to be called as SUPERUSER
SELECT * FROM pg_buffercache_evict(1);
ERROR: must be superuser to use pg_buffercache_evict()
SELECT * FROM pg_buffercache_evict_relation(1);
ERROR: must be superuser to use pg_buffercache_evict_relation()
SELECT * FROM pg_buffercache_evict_all();
ERROR: must be superuser to use pg_buffercache_evict_all()
SELECT * FROM pg_buffercache_mark_dirty(1);
ERROR: must be superuser to use pg_buffercache_mark_dirty()
SELECT * FROM pg_buffercache_mark_dirty_relation(1);
ERROR: must be superuser to use pg_buffercache_mark_dirty_relation()
SELECT * FROM pg_buffercache_mark_dirty_all();
ERROR: must be superuser to use pg_buffercache_mark_dirty_all()
RESET ROLE;
-- These should return nothing, because these are STRICT functions
SELECT * FROM pg_buffercache_evict(NULL);
buffer_evicted | buffer_flushed
----------------+----------------
|
(1 row)
SELECT * FROM pg_buffercache_evict_relation(NULL);
buffers_evicted | buffers_flushed | buffers_skipped
-----------------+-----------------+-----------------
| |
(1 row)
SELECT * FROM pg_buffercache_mark_dirty(NULL);
buffer_dirtied | buffer_already_dirty
----------------+----------------------
|
(1 row)
SELECT * FROM pg_buffercache_mark_dirty_relation(NULL);
buffers_dirtied | buffers_already_dirty | buffers_skipped
-----------------+-----------------------+-----------------
| |
(1 row)
-- These should fail because they are not called by valid range of buffers
-- Number of the shared buffers are limited by max integer
SELECT 2147483647 max_buffers \gset
SELECT * FROM pg_buffercache_evict(-1);
ERROR: bad buffer ID: -1
SELECT * FROM pg_buffercache_evict(0);
ERROR: bad buffer ID: 0
SELECT * FROM pg_buffercache_evict(:max_buffers);
ERROR: bad buffer ID: 2147483647
SELECT * FROM pg_buffercache_mark_dirty(-1);
ERROR: bad buffer ID: -1
SELECT * FROM pg_buffercache_mark_dirty(0);
ERROR: bad buffer ID: 0
SELECT * FROM pg_buffercache_mark_dirty(:max_buffers);
ERROR: bad buffer ID: 2147483647
-- These should fail because they don't accept local relations
CREATE TEMP TABLE temp_pg_buffercache();
SELECT * FROM pg_buffercache_evict_relation('temp_pg_buffercache');
ERROR: relation uses local buffers, pg_buffercache_evict_relation() is intended to be used for shared buffers only
SELECT * FROM pg_buffercache_mark_dirty_relation('temp_pg_buffercache');
ERROR: relation uses local buffers, pg_buffercache_mark_dirty_relation() is intended to be used for shared buffers only
DROP TABLE temp_pg_buffercache;
-- These shouldn't fail
SELECT buffer_evicted IS NOT NULL FROM pg_buffercache_evict(1);
?column?
----------
t
(1 row)
SELECT buffers_evicted IS NOT NULL FROM pg_buffercache_evict_all();
?column?
----------
t
(1 row)
CREATE TABLE shared_pg_buffercache();
SELECT buffers_evicted IS NOT NULL FROM pg_buffercache_evict_relation('shared_pg_buffercache');
?column?
----------
t
(1 row)
SELECT buffers_dirtied IS NOT NULL FROM pg_buffercache_mark_dirty_relation('shared_pg_buffercache');
?column?
----------
t
(1 row)
DROP TABLE shared_pg_buffercache;
SELECT pg_buffercache_mark_dirty(1) IS NOT NULL;
?column?
----------
t
(1 row)
SELECT pg_buffercache_mark_dirty_all() IS NOT NULL;
?column?
----------
t
(1 row)
DROP ROLE regress_buffercache_normal;