MDEV-26223 Galera cluster node consider old server_id value even after...

MDEV-26223 Galera cluster node consider old server_id value even after modification of server_id [wsrep_gtid_mode=ON]

For non bootstrap node server id should be ignored because using custom
value can lead to inconsistency problem with replicated GTID in cluster.
Providing warning message when this happens.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

mysql-test/suite/galera/r/galera_gtid_server_id.result

+connection node_2;
+connection node_1;
+connection node_1;
+select @@gtid_domain_id, @@server_id, @@wsrep_gtid_domain_id,@@wsrep_gtid_mode;
+@@gtid_domain_id	@@server_id	@@wsrep_gtid_domain_id	@@wsrep_gtid_mode
+0	11	1	1
+connection node_2;
+select @@gtid_domain_id, @@server_id, @@wsrep_gtid_domain_id,@@wsrep_gtid_mode;
+@@gtid_domain_id	@@server_id	@@wsrep_gtid_domain_id	@@wsrep_gtid_mode
+0	12	1	1
+connection node_1;
+CREATE TABLE t1(id int not null primary key) engine=innodb;
+INSERT INTO t1 values (1);
+show global variables  like '%gtid%';
+Variable_name	Value
+gtid_binlog_pos	1-11-2
+gtid_binlog_state	1-11-2
+gtid_cleanup_batch_size	64
+gtid_current_pos	1-11-2
+gtid_domain_id	0
+gtid_ignore_duplicates	OFF
+gtid_pos_auto_engines	
+gtid_slave_pos	
+gtid_strict_mode	OFF
+wsrep_gtid_domain_id	1
+wsrep_gtid_mode	ON
+connection node_2;
+SET SESSION wsrep_sync_wait=15;
+show global variables  like '%gtid%';
+Variable_name	Value
+gtid_binlog_pos	1-11-2
+gtid_binlog_state	1-11-2
+gtid_cleanup_batch_size	64
+gtid_current_pos	
+gtid_domain_id	0
+gtid_ignore_duplicates	OFF
+gtid_pos_auto_engines	
+gtid_slave_pos	
+gtid_strict_mode	OFF
+wsrep_gtid_domain_id	1
+wsrep_gtid_mode	ON
+SET GLOBAL server_id=200;
+ERROR 42000: Variable 'server_id' can't be set to the value of '200'
+SHOW WARNINGS;
+Level	Code	Message
+Warning	1231	Can't change server_id because wsrep and wsrep_gtid_mode is set. You can set server_id only with wsrep_new_cluster. 
+Error	1231	Variable 'server_id' can't be set to the value of '200'
+SET SESSION server_id=200;
+ERROR 42000: Variable 'server_id' can't be set to the value of '200'
+SHOW WARNINGS;
+Level	Code	Message
+Warning	1231	Can't change server_id because wsrep and wsrep_gtid_mode is set. You can set server_id only with wsrep_new_cluster. 
+Error	1231	Variable 'server_id' can't be set to the value of '200'
+INSERT INTO t1 values(2);
+show global variables  like '%gtid%';
+Variable_name	Value
+gtid_binlog_pos	1-11-3
+gtid_binlog_state	1-11-3
+gtid_cleanup_batch_size	64
+gtid_current_pos	
+gtid_domain_id	0
+gtid_ignore_duplicates	OFF
+gtid_pos_auto_engines	
+gtid_slave_pos	
+gtid_strict_mode	OFF
+wsrep_gtid_domain_id	1
+wsrep_gtid_mode	ON
+connection node_1;
+show global variables  like '%gtid%';
+Variable_name	Value
+gtid_binlog_pos	1-11-3
+gtid_binlog_state	1-11-3
+gtid_cleanup_batch_size	64
+gtid_current_pos	1-11-3
+gtid_domain_id	0
+gtid_ignore_duplicates	OFF
+gtid_pos_auto_engines	
+gtid_slave_pos	
+gtid_strict_mode	OFF
+wsrep_gtid_domain_id	1
+wsrep_gtid_mode	ON
+DROP TABLE t1;

mysql-test/suite/galera/t/galera_gtid_server_id.cnf

+!include ../galera_2nodes.cnf
+
+[mysqld.1]
+wsrep_gtid_domain_id=1
+wsrep_gtid_mode=ON
+server-id=11
+log_slave_updates
+log_bin
+
+[mysqld.2]
+wsrep_gtid_domain_id=1
+wsrep_gtid_mode=ON
+server-id=12
+log_slave_updates
+log_bin
+

mysql-test/suite/galera/t/galera_gtid_server_id.test

+--source include/galera_cluster.inc
+
+--connection node_1
+select @@gtid_domain_id, @@server_id, @@wsrep_gtid_domain_id,@@wsrep_gtid_mode;
+--connection node_2
+select @@gtid_domain_id, @@server_id, @@wsrep_gtid_domain_id,@@wsrep_gtid_mode;
+
+--connection node_1
+CREATE TABLE t1(id int not null primary key) engine=innodb;
+INSERT INTO t1 values (1);
+show global variables  like '%gtid%';
+--connection node_2
+SET SESSION wsrep_sync_wait=15;
+show global variables  like '%gtid%';
+# This should give error
+--error ER_WRONG_VALUE_FOR_VAR
+SET GLOBAL server_id=200;
+SHOW WARNINGS;
+# This should give error
+--error ER_WRONG_VALUE_FOR_VAR
+SET SESSION server_id=200;
+SHOW WARNINGS;
+INSERT INTO t1 values(2);
+show global variables  like '%gtid%';
+--connection node_1
+show global variables  like '%gtid%';
+DROP TABLE t1;

sql/sys_vars.cc

@@ -3223,6 +3223,21 @@ static Sys_var_charptr_fscs Sys_secure_file_priv(
        PREALLOCATED READ_ONLY GLOBAL_VAR(opt_secure_file_priv),
        CMD_LINE(REQUIRED_ARG), DEFAULT(0));
 
+static bool check_server_id(sys_var *self, THD *thd, set_var *var)
+{
+#ifdef WITH_WSREP
+  if (WSREP_ON && WSREP_PROVIDER_EXISTS && !wsrep_new_cluster && wsrep_gtid_mode)
+  {
+    push_warning(thd, Sql_condition::WARN_LEVEL_WARN,
+                 ER_WRONG_VALUE_FOR_VAR,
+                 "Can't change server_id because wsrep and wsrep_gtid_mode is set."
+                 " You can set server_id only with wsrep_new_cluster. ");
+    return true;
+  }
+#endif /* WITH_WSREP */
+  return false;
+}
+
 static bool fix_server_id(sys_var *self, THD *thd, enum_var_type type)
 {
   if (type == OPT_GLOBAL)
@@ -3247,7 +3262,7 @@ Sys_server_id(
        "replication partners",
        SESSION_VAR(server_id), CMD_LINE(REQUIRED_ARG, OPT_SERVER_ID),
        VALID_RANGE(1, UINT_MAX32), DEFAULT(1), BLOCK_SIZE(1), NO_MUTEX_GUARD,
-       NOT_IN_BINLOG, ON_CHECK(0), ON_UPDATE(fix_server_id));
+       NOT_IN_BINLOG, ON_CHECK(check_server_id), ON_UPDATE(fix_server_id));
 
 static Sys_var_on_access_global<Sys_var_mybool,
                           PRIV_SET_SYSTEM_GLOBAL_VAR_SLAVE_COMPRESSED_PROTOCOL>

sql/wsrep_mysqld.cc

@@ -802,7 +802,6 @@ int wsrep_init_server()
 
 void wsrep_init_globals()
 {
-  wsrep_gtid_server.domain_id= wsrep_gtid_domain_id;
   wsrep_init_sidno(Wsrep_server_state::instance().connected_gtid().id());
   /* Recover last written wsrep gtid */
   wsrep_init_gtid();
@@ -817,6 +816,13 @@ void wsrep_init_globals()
     wsrep_get_binlog_gtid_seqno(new_gtid);
     wsrep_gtid_server.gtid(new_gtid);
   }
+  else
+  {
+    if (wsrep_gtid_mode && wsrep_gtid_server.server_id != global_system_variables.server_id)
+    {
+      WSREP_WARN("Ignoring server id for non bootstrap node.");
+    }
+  }
   wsrep_init_schema();
   if (WSREP_ON)
   {