MDEV-19801: Change defaults for CHANGE MASTER TO so that GTID-based replication is used by default if master supports it

This commit makes replicas crash-safe by default by changing the
Using_Gtid value to be Slave_Pos on a fresh slave start and after
RESET SLAVE is issued. If the primary server does not support GTIDs
(i.e., version < 10), the replica will fall back to Using_Gtid=No on
slave start and after RESET SLAVE.

The following additional informational messages/warnings are added:

 1. When Using_Gtid is automatically changed. That is, if RESET
SLAVE reverts Using_Gtid back to Slave_Pos, or Using_Gtid is
inferred to No from a CHANGE MASTER TO given with log coordinates
without MASTER_USE_GTID.
 2. If options are ignored in CHANGE MASTER TO. If CHANGE MASTER TO
is given with log coordinates, yet also specifies
MASTER_USE_GTID=Slave_Pos, a warning message is given that the log
coordinate options are ignored.

Additionally, an MTR macro has been added for RESET SLAVE,
reset_slave.inc, which provides modes/options for resetting a slave
in log coordinate or gtid modes. When in log coordinates mode, the
macro will execute CHANGE MASTER TO MASTER_USE_GTID=No after the
RESET SLAVE command. When in GTID mode, an extra parameter,
reset_slave_keep_gtid_state, can be set to reset or preserve the
value of gtid_slave_pos.

Reviewed By:
===========
Andrei Elkin <andrei.elkin@mariadb.com>

mysql-test/include/check-testcase.test

@@ -62,7 +62,7 @@ if ($tmp)
   --echo Master_Server_Id	#
   --echo Master_SSL_Crl	#
   --echo Master_SSL_Crlpath	#
-  --echo Using_Gtid	No
+  --echo Using_Gtid	Slave_Pos
   --echo Gtid_IO_Pos	#
   --echo Replicate_Do_Domain_Ids	
   --echo Replicate_Ignore_Domain_Ids	

mysql-test/include/reset_slave.inc

@@ -0,0 +1,58 @@
+# ==== Purpose ====
+#
+# Reset the slave on the active connection
+#
+#
+# ==== Usage ====
+#
+# [--let $master_use_gtid_option= NO]
+# --source include/rpl_reset_slave.inc
+#
+# Parameters:
+#   $master_use_gtid_option
+#     Sets the context for the reset slave. When No, execute
+#     CHANGE MASTER TO MASTER_USE_GTID=No after the RESET SLAVE. When
+#     Slave_Pos, execute set gtid_slave_pos= "" after RESET SLAVE.
+#
+#   $reset_slave_keep_gtid_state
+#     When master_use_gtid_option is Slave_Pos, this defines whether or not
+#     gtid_slave_pos will be reset as well. Accepted values are of boolean
+#     type. Default value is false.
+#
+
+--let $include_filename= reset_slave.inc
+--source include/begin_include_file.inc
+
+
+if (!$rpl_debug)
+{
+  --disable_query_log
+}
+
+if (!$master_use_gtid_option)
+{
+  --let $master_use_gtid_option= Slave_Pos
+}
+
+if (!$reset_slave_keep_gtid_state)
+{
+  --let $reset_slave_keep_gtid_state=0
+}
+
+if (`SELECT strcmp("$master_use_gtid_option","Slave_Pos") != 0 AND strcmp("$master_use_gtid_option","No") != 0`)
+{
+  die Invalid option provided as master_use_gtid_option, Slave_Pos or No are the only allowed options;
+}
+
+RESET SLAVE;
+if (`SELECT strcmp("$master_use_gtid_option","Slave_Pos") = 0 AND NOT $reset_slave_keep_gtid_state`)
+{
+  SET @@GLOBAL.gtid_slave_pos= "";
+}
+if (`SELECT strcmp("$master_use_gtid_option","No") = 0`)
+{
+  CHANGE MASTER TO MASTER_USE_GTID=No;
+}
+
+--let $include_filename= reset_slave.inc
+--source include/end_include_file.inc

mysql-test/include/rpl_change_topology.inc

@@ -225,7 +225,14 @@ if (!$rpl_skip_change_master)
       {
         --let $_rpl_master_log_pos=
       }
-      eval CHANGE MASTER TO MASTER_HOST = '127.0.0.1', MASTER_PORT = $_rpl_port, MASTER_USER = 'root', MASTER_LOG_FILE = '$_rpl_master_log_file'$_rpl_master_log_pos, MASTER_CONNECT_RETRY = 1;
+      if ($rpl_master_log_file)
+      {
+        eval CHANGE MASTER TO MASTER_HOST = '127.0.0.1', MASTER_PORT = $_rpl_port, MASTER_USER = 'root', MASTER_LOG_FILE = '$_rpl_master_log_file'$_rpl_master_log_pos, MASTER_CONNECT_RETRY = 1, MASTER_USE_GTID=NO;
+      }
+      if (!$rpl_master_log_file)
+      {
+        eval CHANGE MASTER TO MASTER_HOST = '127.0.0.1', MASTER_PORT = $_rpl_port, MASTER_USER = 'root', MASTER_CONNECT_RETRY=1;
+      }
     }
     if ($_rpl_master == '')
     {

mysql-test/include/rpl_end.inc

@@ -90,7 +90,7 @@ while ($_rpl_server)
   --source include/rpl_connection.inc
 
   # Clear Using_Gtid in SHOW SLAVE STATUS to keep check_testcase happy.
-  CHANGE MASTER TO master_log_file='';
+  CHANGE MASTER TO master_use_gtid=Slave_Pos;
 
   --dec $_rpl_server
 }

mysql-test/include/rpl_reset.inc

@@ -63,13 +63,13 @@ while ($_rpl_server)
   --let $rpl_connection_name= server_$_rpl_server
   --source include/rpl_connection.inc
 
+  RESET MASTER;
   # Check if this server is configured to have a master
   if (`SELECT SUBSTRING('$rpl_master_list', 1 + ($_rpl_server - 1) * $rpl_server_count_length, $rpl_server_count_length) != ''`)
   {
     --source include/stop_slave.inc
-    RESET SLAVE;
+    --source include/reset_slave.inc
   }
-  RESET MASTER;
   --dec $_rpl_server
 }
 

mysql-test/include/setup_fake_relay_log.inc

@@ -100,7 +100,7 @@ RESET SLAVE;
 --let $_fake_old_master_host= query_get_value(SHOW SLAVE STATUS, Master_Host, 1)
 
 # Setup replication from existing relay log.
-eval CHANGE MASTER TO MASTER_HOST='dummy.localdomain', RELAY_LOG_FILE='$_fake_filename-fake.000001', RELAY_LOG_POS=4;
+eval CHANGE MASTER TO MASTER_HOST='dummy.localdomain', RELAY_LOG_FILE='$_fake_filename-fake.000001', RELAY_LOG_POS=4, MASTER_USE_GTID=NO;
 
 --let $include_filename= setup_fake_relay_log.inc
 --source include/end_include_file.inc

mysql-test/include/test_fieldsize.inc

@@ -11,7 +11,8 @@ DROP TABLE IF EXISTS t1;
 
 sync_slave_with_master;
 STOP SLAVE;
-RESET SLAVE;
+--let $master_use_gtid_option= No
+--source include/reset_slave.inc
 eval $test_table_slave;
 
 connection master;
@@ -29,7 +30,7 @@ START SLAVE;
 # The following should be 0
 SELECT COUNT(*) FROM t1;
 STOP SLAVE;
-RESET SLAVE;
+--source include/reset_slave.inc
 
 connection master;
 RESET MASTER;