From bc6121819cf648237d0c2c63e48d53acf816db76 Mon Sep 17 00:00:00 2001
From: Andrei Elkin <andrei.elkin@mariadb.com>
Date: Mon, 16 Dec 2024 19:34:09 +0200
Subject: [PATCH] MDEV-35098 rpl.rpl_mysqldump_gtid_slave_pos fails in buildbot

The test turns out to be senstive to @@global.gtid_cleanup_batch_size.
With a rather small default value of the latter
SELECTing from mysql.gtid_slave_pos may not be deterministic: tests
that run before may increase a pending for automitic deletion batch.

The test is refined to set its own value for the batch size which
is virtually unreachable.

Thanks to Kristian Nielsen for the analysis.
---
 .../suite/rpl/r/rpl_mysqldump_gtid_slave_pos.result       | 4 ++++
 mysql-test/suite/rpl/t/rpl_mysqldump_gtid_slave_pos.test  | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/mysql-test/suite/rpl/r/rpl_mysqldump_gtid_slave_pos.result b/mysql-test/suite/rpl/r/rpl_mysqldump_gtid_slave_pos.result
index 1849f896758..9340498c537 100644
--- a/mysql-test/suite/rpl/r/rpl_mysqldump_gtid_slave_pos.result
+++ b/mysql-test/suite/rpl/r/rpl_mysqldump_gtid_slave_pos.result
@@ -32,6 +32,7 @@ insert into t1 set a = 2;
 insert into t1 set a = 1;
 include/save_master_gtid.inc
 connection slave;
+SET @@global.gtid_cleanup_batch_size = $val;
 include/start_slave.inc
 include/sync_with_master_gtid.inc
 select * from mysql.gtid_slave_pos;
@@ -55,6 +56,7 @@ set statement sql_log_bin=0 for delete from mysql.gtid_slave_pos;
 insert into mysql.gtid_slave_pos values (99 + 2, 1, 1, 1);
 # 5.
 include/rpl_restart_server.inc [server_number=2]
+SET @@global.gtid_cleanup_batch_size = $val;
 select * from mysql.gtid_slave_pos;
 domain_id	sub_id	server_id	seq_no
 101	1	1	1
@@ -99,6 +101,7 @@ set statement sql_log_bin=0 for delete from mysql.gtid_slave_pos;
 insert into mysql.gtid_slave_pos values (99 + 1, 1, 1, 1);
 # 5.
 include/rpl_restart_server.inc [server_number=2]
+SET @@global.gtid_cleanup_batch_size = $val;
 select * from mysql.gtid_slave_pos;
 domain_id	sub_id	server_id	seq_no
 100	1	1	1
@@ -145,5 +148,6 @@ connection master;
 DROP TABLE t1;
 include/save_master_gtid.inc
 connection slave;
+SET @@global.gtid_cleanup_batch_size= $old_gtid_cleanup_batch_size;
 include/sync_with_master_gtid.inc
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_mysqldump_gtid_slave_pos.test b/mysql-test/suite/rpl/t/rpl_mysqldump_gtid_slave_pos.test
index e66a92a6153..820fc56134b 100644
--- a/mysql-test/suite/rpl/t/rpl_mysqldump_gtid_slave_pos.test
+++ b/mysql-test/suite/rpl/t/rpl_mysqldump_gtid_slave_pos.test
@@ -47,6 +47,12 @@ while ($i)
 --source include/save_master_gtid.inc
 
 --connection slave
+# enforce determistic SELECT * from mysql.gtid_slave_pos
+--let $old_gtid_cleanup_batch_size = `select @@GLOBAL.gtid_cleanup_batch_size`
+# the number of generated transactions on master must not exceed this value:
+--let $val= 2147483647
+--evalp SET @@global.gtid_cleanup_batch_size = $val
+
 --source include/start_slave.inc
 --source include/sync_with_master_gtid.inc
 # Prior tests in a mtr batch could leave the min value of sub_id column with
@@ -85,6 +91,7 @@ while ($i)
   --echo # 5.
   --let $rpl_server_number= 2
   --source include/rpl_restart_server.inc
+  --evalp SET @@global.gtid_cleanup_batch_size = $val
   select * from mysql.gtid_slave_pos;
   select @@global.gtid_slave_pos as "before dump restore";
   --let $dump=dump_$i.sql
@@ -130,6 +137,7 @@ DROP TABLE t1;
 --source include/save_master_gtid.inc
 
 --connection slave
+--evalp SET @@global.gtid_cleanup_batch_size= $old_gtid_cleanup_batch_size
 --remove_files_wildcard $MYSQLTEST_VARDIR/tmp dump_*.sql
 --source include/sync_with_master_gtid.inc