pg_buffercache: Add pg_buffercache_mark_dirty{,_relation,_all}()

This commit introduces three new functions for marking shared buffers as
dirty by using the functions introduced in 9660906dbd69:
* pg_buffercache_mark_dirty() for one shared buffer.
- pg_buffercache_mark_dirt_relation() for all the shared buffers in a
relation.
* pg_buffercache_mark_dirty_all() for all the shared buffers in pool.

The "_all" and "_relation" flavors are designed to address the
inefficiency of repeatedly calling pg_buffercache_mark_dirty() for each
individual buffer, which can be time-consuming when dealing with with
large shared buffers pool.

These functions are intended as developer tools and are available only
to superusers.  There is no need to bump the version of pg_buffercache,
4b203d499c61 having done this job in this release cycle.

Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Aidar Imamov <a.imamov@postgrespro.ru>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Joseph Koshakow <koshy44@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Yuhang Qiu <iamqyh@gmail.com>
Reviewed-by: Xuneng Zhou <xunengzhou@gmail.com>
Discussion: https://postgr.es/m/CAN55FZ0h_YoSqqutxV6DES1RW8ig6wcA8CR9rJk358YRMxZFmw@mail.gmail.com

1 files changed, 14 insertions, 3 deletions

diff --git a/contrib/pg_buffercache/sql/pg_buffercache.sql b/contrib/pg_buffercache/sql/pg_buffercache.sql
index 3c70ee9ef4a..127d604905c 100644
--- a/contrib/pg_buffercache/sql/pg_buffercache.sql
+++ b/contrib/pg_buffercache/sql/pg_buffercache.sql
@@ -38,7 +38,7 @@ RESET role;
 
 
 ------
----- Test pg_buffercache_evict* functions
+---- Test pg_buffercache_evict* and pg_buffercache_mark_dirty* functions
 ------
 
 CREATE ROLE regress_buffercache_normal;
@@ -48,12 +48,17 @@ SET ROLE regress_buffercache_normal;
 SELECT * FROM pg_buffercache_evict(1);
 SELECT * FROM pg_buffercache_evict_relation(1);
 SELECT * FROM pg_buffercache_evict_all();
+SELECT * FROM pg_buffercache_mark_dirty(1);
+SELECT * FROM pg_buffercache_mark_dirty_relation(1);
+SELECT * FROM pg_buffercache_mark_dirty_all();
 
 RESET ROLE;
 
 -- These should return nothing, because these are STRICT functions
 SELECT * FROM pg_buffercache_evict(NULL);
 SELECT * FROM pg_buffercache_evict_relation(NULL);
+SELECT * FROM pg_buffercache_mark_dirty(NULL);
+SELECT * FROM pg_buffercache_mark_dirty_relation(NULL);
 
 -- These should fail because they are not called by valid range of buffers
 -- Number of the shared buffers are limited by max integer
@@ -61,11 +66,14 @@ SELECT 2147483647 max_buffers \gset
 SELECT * FROM pg_buffercache_evict(-1);
 SELECT * FROM pg_buffercache_evict(0);
 SELECT * FROM pg_buffercache_evict(:max_buffers);
+SELECT * FROM pg_buffercache_mark_dirty(-1);
+SELECT * FROM pg_buffercache_mark_dirty(0);
+SELECT * FROM pg_buffercache_mark_dirty(:max_buffers);
 
--- This should fail because pg_buffercache_evict_relation() doesn't accept
--- local relations
+-- 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');
+SELECT * FROM pg_buffercache_mark_dirty_relation('temp_pg_buffercache');
 DROP TABLE temp_pg_buffercache;
 
 -- These shouldn't fail
@@ -73,6 +81,9 @@ SELECT buffer_evicted IS NOT NULL FROM pg_buffercache_evict(1);
 SELECT buffers_evicted IS NOT NULL FROM pg_buffercache_evict_all();
 CREATE TABLE shared_pg_buffercache();
 SELECT buffers_evicted IS NOT NULL FROM pg_buffercache_evict_relation('shared_pg_buffercache');
+SELECT buffers_dirtied IS NOT NULL FROM pg_buffercache_mark_dirty_relation('shared_pg_buffercache');
 DROP TABLE shared_pg_buffercache;
+SELECT pg_buffercache_mark_dirty(1) IS NOT NULL;
+SELECT pg_buffercache_mark_dirty_all() IS NOT NULL;
 
 DROP ROLE regress_buffercache_normal;