MDEV-20122: Deprecate MASTER_USE_GTID=Current_Pos to favor new MASTER_DEMOTE_TO_SLAVE option

New Feature:
========
This feature adds a safe replacement to the
MASTER_USE_GTID=Current_Pos option for CHANGE MASTER TO as
MASTER_DEMOTE_TO_SLAVE=<bool>. The use case of Current_Pos is to
transition a master to become a slave; however, can break
replication state if the slave executes local transactions due to
actively updating gtid_current_pos with gtid_binlog_pos and
gtid_slave_pos.

MASTER_DEMOTE_TO_SLAVE changes this use case by forcing users to set
Using_Gtid=Slave_Pos and merging gtid_binlog_pos into gtid_slave_pos
once at CHANGE MASTER TO time. Note that if gtid_slave_pos is more
recent than gtid_binlog_pos (as in the case of chain replication),
the replication state should be preserved.

Additionally, deprecate the `Current_Pos` option of MASTER_USE_GTID
to suggest the safe alternative option MASTER_DEMOTE_TO_SLAVE=TRUE.

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

mysql-test/suite/binlog_encryption/rpl_gtid_basic.result

@@ -69,6 +69,8 @@ INSERT INTO t2 VALUES (5, "i1a");
 connection server_4;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 SELECT * FROM t1 ORDER BY a;
 a	b
@@ -89,6 +91,8 @@ connection server_2;
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_4,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_4;
 UPDATE t2 SET b="j1a" WHERE a=5;
@@ -117,6 +121,8 @@ include/save_master_gtid.inc
 connection server_3;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_4,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 include/sync_with_master_gtid.inc
 SELECT * FROM t2 ORDER BY a;

mysql-test/suite/engines/funcs/r/rpl_change_master.result

@@ -26,4 +26,9 @@ connection master;
 CHANGE MASTER TO MASTER_USER='root', MASTER_SSL=0, MASTER_SSL_CA='', MASTER_SSL_CERT='',
 MASTER_SSL_KEY='', MASTER_SSL_CRL='', MASTER_SSL_CRLPATH='';
 CHANGE MASTER TO MASTER_USER='root', MASTER_PASSWORD='', MASTER_SSL=0;
+"Usage of CURRENT_POS in CHANGE MASTER  MASTER_USE_GTID is dreprecated.
+CHANGE MASTER TO MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
+CHANGE MASTER TO MASTER_USE_GTID=SLAVE_POS;
 include/rpl_end.inc

mysql-test/suite/multi_source/gtid.result

@@ -48,7 +48,11 @@ INSERT INTO t2 VALUES (2, "switch1");
 INSERT INTO t3 VALUES (202, "switch1 b");
 connection slave2;
 CHANGE MASTER 'slave1' TO master_port=MYPORT_1, master_host='127.0.0.1', master_user='root', master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 CHANGE MASTER 'slave2' TO master_port=MYPORT_2, master_host='127.0.0.1', master_user='root', master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 SET default_master_connection = 'slave1';
 START SLAVE;
 include/wait_for_slave_to_start.inc
@@ -76,6 +80,8 @@ connection slave2;
 include/sync_with_master_gtid.inc
 connection slave1;
 CHANGE MASTER TO master_port=MYPORT_4, master_host='127.0.0.1', master_user='root', master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE;
 SELECT * FROM t1 ORDER BY a;
 a	b

mysql-test/suite/perfschema/r/digest_view.result

@@ -191,17 +191,17 @@ SELECT SCHEMA_NAME, DIGEST, DIGEST_TEXT, COUNT_STAR
 FROM performance_schema.events_statements_summary_by_digest
 ORDER BY DIGEST_TEXT;
 SCHEMA_NAME	DIGEST	DIGEST_TEXT	COUNT_STAR
-test	27a9ab161a63050c84a63c6f77ebeb33	EXPLAIN SELECT * FROM `test` . `v1` 	1
-test	ab0ab27c04f3a294feb86bede4331f86	EXPLAIN SELECT * FROM `test` . `v1` WHERE `a` = ? 	1
-test	2e722346a5c2ef820946bcd04ccac208	EXPLAIN SELECT * FROM `test` . `v1` WHERE `b` > ? 	1
-test	07baf2264db30b6b25302603436ebe82	EXPLAIN SELECT `a` , `b` FROM `test` . `v1` 	1
-test	3a7dbc963635ab0de6e160e0a4212bce	EXPLAIN SELECT `b` , `a` FROM `test` . `v1` 	1
-test	6b845c2e3a7421997e3b610d14b5c842	SELECT * FROM `test` . `v1` 	1
-test	cb2ee099edbf6e0e5ee6ae14f3b1498a	SELECT * FROM `test` . `v1` WHERE `a` = ? 	1
-test	e2dc5a300d2ba54ebb987a2ca6b90d93	SELECT * FROM `test` . `v1` WHERE `b` > ? 	1
-test	c68e0f99323f7bb7732c7b5cf32c0ec2	SELECT `a` , `b` FROM `test` . `v1` 	1
-test	43c5de955c9a72d2bb6f49db5c0ad3e7	SELECT `b` , `a` FROM `test` . `v1` 	1
-test	1678258ba15f7ccc63fd7b833763914a	TRUNCATE TABLE `performance_schema` . `events_statements_summary_by_digest` 	1
+test	333a53e537d74bf74dd28c78ad5b23dd	EXPLAIN SELECT * FROM `test` . `v1` 	1
+test	1fb578da66e6583bae8e64061486f1b1	EXPLAIN SELECT * FROM `test` . `v1` WHERE `a` = ? 	1
+test	923bca939a55826e231e1335016ba418	EXPLAIN SELECT * FROM `test` . `v1` WHERE `b` > ? 	1
+test	6fa6d75432fd499d1c7d6f964c8310a2	EXPLAIN SELECT `a` , `b` FROM `test` . `v1` 	1
+test	3421da1ec8ecb8cac97e12a0609f73cb	EXPLAIN SELECT `b` , `a` FROM `test` . `v1` 	1
+test	c2f68fd41bfbf3acd52eb5e7306b0c00	SELECT * FROM `test` . `v1` 	1
+test	dd68812cbe4c1ed5a38921222981f8c5	SELECT * FROM `test` . `v1` WHERE `a` = ? 	1
+test	7563bcc32c6d0d872c8d9f0bf7717e6a	SELECT * FROM `test` . `v1` WHERE `b` > ? 	1
+test	0817c53833dc6adbca581e8fe4c598c7	SELECT `a` , `b` FROM `test` . `v1` 	1
+test	a5f13903c70812ae08fa8c084e9cd503	SELECT `b` , `a` FROM `test` . `v1` 	1
+test	66b14a14f2a42e1335dd28dfad8ea084	TRUNCATE TABLE `performance_schema` . `events_statements_summary_by_digest` 	1
 DROP TABLE test.v1;
 CREATE VIEW test.v1 AS SELECT * FROM test.t1;
 EXPLAIN SELECT * from test.v1;
@@ -248,19 +248,19 @@ SELECT SCHEMA_NAME, DIGEST, DIGEST_TEXT, COUNT_STAR
 FROM performance_schema.events_statements_summary_by_digest
 ORDER BY DIGEST_TEXT;
 SCHEMA_NAME	DIGEST	DIGEST_TEXT	COUNT_STAR
-test	342cd5e41944d5f857f92b1e374857de	CREATE VIEW `test` . `v1` AS SELECT * FROM `test` . `t1` 	1
-test	2653f30030efcb6125121daa8eadf418	DROP TABLE `test` . `v1` 	1
-test	27a9ab161a63050c84a63c6f77ebeb33	EXPLAIN SELECT * FROM `test` . `v1` 	2
-test	ab0ab27c04f3a294feb86bede4331f86	EXPLAIN SELECT * FROM `test` . `v1` WHERE `a` = ? 	2
-test	2e722346a5c2ef820946bcd04ccac208	EXPLAIN SELECT * FROM `test` . `v1` WHERE `b` > ? 	2
-test	07baf2264db30b6b25302603436ebe82	EXPLAIN SELECT `a` , `b` FROM `test` . `v1` 	2
-test	3a7dbc963635ab0de6e160e0a4212bce	EXPLAIN SELECT `b` , `a` FROM `test` . `v1` 	2
-test	6b845c2e3a7421997e3b610d14b5c842	SELECT * FROM `test` . `v1` 	2
-test	cb2ee099edbf6e0e5ee6ae14f3b1498a	SELECT * FROM `test` . `v1` WHERE `a` = ? 	2
-test	e2dc5a300d2ba54ebb987a2ca6b90d93	SELECT * FROM `test` . `v1` WHERE `b` > ? 	2
-test	a13cfeda6d474d29546719d76dcfa831	SELECT SCHEMA_NAME , `DIGEST` , `DIGEST_TEXT` , `COUNT_STAR` FROM `performance_schema` . `events_statements_summary_by_digest` ORDER BY `DIGEST_TEXT` 	1
-test	c68e0f99323f7bb7732c7b5cf32c0ec2	SELECT `a` , `b` FROM `test` . `v1` 	2
-test	43c5de955c9a72d2bb6f49db5c0ad3e7	SELECT `b` , `a` FROM `test` . `v1` 	2
-test	1678258ba15f7ccc63fd7b833763914a	TRUNCATE TABLE `performance_schema` . `events_statements_summary_by_digest` 	1
+test	98531b331031b84ddfbb2de8b601a704	CREATE VIEW `test` . `v1` AS SELECT * FROM `test` . `t1` 	1
+test	5352d7d117e97fecd312e354e9e290ce	DROP TABLE `test` . `v1` 	1
+test	333a53e537d74bf74dd28c78ad5b23dd	EXPLAIN SELECT * FROM `test` . `v1` 	2
+test	1fb578da66e6583bae8e64061486f1b1	EXPLAIN SELECT * FROM `test` . `v1` WHERE `a` = ? 	2
+test	923bca939a55826e231e1335016ba418	EXPLAIN SELECT * FROM `test` . `v1` WHERE `b` > ? 	2
+test	6fa6d75432fd499d1c7d6f964c8310a2	EXPLAIN SELECT `a` , `b` FROM `test` . `v1` 	2
+test	3421da1ec8ecb8cac97e12a0609f73cb	EXPLAIN SELECT `b` , `a` FROM `test` . `v1` 	2
+test	c2f68fd41bfbf3acd52eb5e7306b0c00	SELECT * FROM `test` . `v1` 	2
+test	dd68812cbe4c1ed5a38921222981f8c5	SELECT * FROM `test` . `v1` WHERE `a` = ? 	2
+test	7563bcc32c6d0d872c8d9f0bf7717e6a	SELECT * FROM `test` . `v1` WHERE `b` > ? 	2
+test	21c19dd7ef5b894f3e32d0585cb3007f	SELECT SCHEMA_NAME , `DIGEST` , `DIGEST_TEXT` , `COUNT_STAR` FROM `performance_schema` . `events_statements_summary_by_digest` ORDER BY `DIGEST_TEXT` 	1
+test	0817c53833dc6adbca581e8fe4c598c7	SELECT `a` , `b` FROM `test` . `v1` 	2
+test	a5f13903c70812ae08fa8c084e9cd503	SELECT `b` , `a` FROM `test` . `v1` 	2
+test	66b14a14f2a42e1335dd28dfad8ea084	TRUNCATE TABLE `performance_schema` . `events_statements_summary_by_digest` 	1
 DROP VIEW test.v1;
 DROP TABLE test.t1;

mysql-test/suite/perfschema/r/start_server_low_digest_sql_length.result

@@ -8,5 +8,5 @@ SELECT 1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1
 ####################################
 SELECT event_name, digest, digest_text, sql_text FROM events_statements_history_long;
 event_name	digest	digest_text	sql_text
-statement/sql/select	1fd0cdb6b5aa22bd0809a39b2dc2ac70	SELECT ? + ? + 	SELECT ...
-statement/sql/truncate	0a9c405cebde6df4be315dae86ff398a	TRUNCATE TABLE 	truncat...
+statement/sql/select	96a6bb95edaf100857f09c968aca354b	SELECT ? + ? + 	SELECT ...
+statement/sql/truncate	c1d647bb870f2c63c22a16707bb8aee3	TRUNCATE TABLE 	truncat...

mysql-test/suite/rpl/include/rpl_change_master_demote.inc

+#
+# This file tests that a master can be demoted to a slave using
+# CHANGE MASTER TO MASTER_DEMOTE_TO_SLAVE=1 and replication will work correctly
+# afterwards.
+#
+# param $ignore_domain_ids : List of GTID domain ids to use for
+#                            CHANGE MASTER TO IGNORE_DOMAIN_IDS
+#
+
+--let $include_filename= rpl_change_master_demote.inc
+--source include/begin_include_file.inc
+
+--echo ##############################################
+--echo # Connection semantics change:
+--echo #  * True primary is now connection 'slave'
+--echo #  * True replica is now connection 'master'
+--echo ##############################################
+
+--connection master
+SELECT VARIABLE_NAME, GLOBAL_VALUE FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE VARIABLE_NAME LIKE 'gtid_binlog_pos' OR VARIABLE_NAME LIKE 'gtid_slave_pos' OR VARIABLE_NAME LIKE 'gtid_current_pos' ORDER BY VARIABLE_NAME ASC;
+
+--let $extra_cm_args=
+if (`SELECT strcmp("$ignore_domain_ids","") != 0`)
+{
+    --let $extra_cm_args=, ignore_domain_ids=($ignore_domain_ids)
+}
+
+--echo # First ensure gtid_slave_pos after master_demote_to_slave matches
+--echo # gtid_current_pos calculation
+--let $current_pos= `SELECT @@gtid_current_pos`
+--replace_result $SLAVE_MYPORT SLAVE_PORT
+--eval CHANGE MASTER TO master_host='127.0.0.1', master_port=$SLAVE_MYPORT, master_user='root', master_use_gtid=slave_pos, master_demote_to_slave=1 $extra_cm_args
+SELECT VARIABLE_NAME, GLOBAL_VALUE FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE VARIABLE_NAME LIKE 'gtid_binlog_pos' OR VARIABLE_NAME LIKE 'gtid_slave_pos' OR VARIABLE_NAME LIKE 'gtid_current_pos' ORDER BY VARIABLE_NAME ASC;
+--let $slave_pos= `SELECT @@gtid_slave_pos`
+--echo # Validating gtid_slave_pos == gtid_binlog_pos..
+if ($slave_pos != $current_pos)
+{
+    SELECT VARIABLE_NAME, GLOBAL_VALUE FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE VARIABLE_NAME LIKE 'gtid_binlog_pos' OR VARIABLE_NAME LIKE 'gtid_slave_pos' OR VARIABLE_NAME LIKE 'gtid_current_pos' ORDER BY VARIABLE_NAME ASC;
+    die gtid_slave_pos calculation after master_demote_to_slave=1 differs from gtid_current_pos;
+}
+--echo # ..success
+
+--source include/start_slave.inc
+
+--connection slave
+--source include/stop_slave.inc
+
+--echo # Ensuring replication works correctly after role swap
+--connection slave
+set session gtid_domain_id= 0;
+CREATE TABLE repl_t (a int);
+INSERT INTO repl_t VALUES (1);
+--source include/save_master_gtid.inc
+
+--connection master
+--source include/sync_with_master_gtid.inc
+--echo # Validating that replication works..
+--let $n_replicated_rows= query_get_value(SELECT COUNT(*) FROM repl_t, COUNT(*), 1)
+if ($n_replicated_rows != 1)
+{
+    die "Replication is broken";
+}
+--echo # ..success
+
+--echo # Cleaning up replication check data
+--connection slave
+DROP TABLE repl_t;
+--source include/save_master_gtid.inc
+
+--connection master
+--source include/sync_with_master_gtid.inc
+SELECT VARIABLE_NAME, GLOBAL_VALUE FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES WHERE VARIABLE_NAME LIKE 'gtid_binlog_pos' OR VARIABLE_NAME LIKE 'gtid_slave_pos' OR VARIABLE_NAME LIKE 'gtid_current_pos' ORDER BY VARIABLE_NAME ASC;
+
+--echo ##############################################
+--echo # Connection semantics change:
+--echo #  * True primary is back to connection 'master'
+--echo #  * True replica is back to connection 'slave'
+--echo ##############################################
+
+--connection master
+--source include/stop_slave.inc
+
+--connection slave
+--replace_result $MASTER_MYPORT MASTER_PORT
+--eval CHANGE MASTER TO master_host='127.0.0.1', master_port=$MASTER_MYPORT, master_user='root', master_use_gtid=slave_pos, master_demote_to_slave=1
+--source include/start_slave.inc
+
+--let $include_filename= rpl_change_master_demote.inc
+--source include/end_include_file.inc

mysql-test/suite/rpl/r/rpl_binlog_dump_slave_gtid_state_info.result

@@ -5,6 +5,8 @@ SET GLOBAL LOG_WARNINGS=2;
 connection slave;
 include/stop_slave.inc
 CHANGE MASTER TO MASTER_USE_GTID=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection master;
 "Test Case 1: Start binlog_dump to slave_server(#), pos(master-bin.000001, ###), using_gtid(1), gtid('')"

mysql-test/suite/rpl/r/rpl_change_master.result

@@ -26,4 +26,9 @@ connection master;
 CHANGE MASTER TO MASTER_USER='root', MASTER_SSL=0, MASTER_SSL_CA='', MASTER_SSL_CERT='',
 MASTER_SSL_KEY='', MASTER_SSL_CRL='', MASTER_SSL_CRLPATH='';
 CHANGE MASTER TO MASTER_USER='root', MASTER_PASSWORD='', MASTER_SSL=0;
+"Usage of CURRENT_POS in CHANGE MASTER  MASTER_USE_GTID is dreprecated.
+CHANGE MASTER TO MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
+CHANGE MASTER TO MASTER_USE_GTID=SLAVE_POS;
 include/rpl_end.inc

mysql-test/suite/rpl/r/rpl_gtid_basic.result

@@ -69,6 +69,8 @@ INSERT INTO t2 VALUES (5, "i1a");
 connection server_4;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 SELECT * FROM t1 ORDER BY a;
 a	b
@@ -89,6 +91,8 @@ connection server_2;
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_4,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_4;
 UPDATE t2 SET b="j1a" WHERE a=5;
@@ -117,6 +121,8 @@ include/save_master_gtid.inc
 connection server_3;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_4,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 include/sync_with_master_gtid.inc
 SELECT * FROM t2 ORDER BY a;

mysql-test/suite/rpl/r/rpl_gtid_crash.result

@@ -15,6 +15,8 @@ SET sql_log_bin=1;
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_1;
 INSERT INTO t1 VALUES (2,1);
 INSERT INTO t1 VALUES (3,1);

mysql-test/suite/rpl/r/rpl_gtid_errorhandling.result

@@ -74,6 +74,8 @@ INSERT INTO t1 VALUES (2);
 SET sql_log_bin = 1;
 INSERT INTO t1 VALUES (3);
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 BEGIN;
 SET GLOBAL gtid_slave_pos = "100-100-100";
 ERROR 25000: You are not allowed to execute this command in a transaction

mysql-test/suite/rpl/r/rpl_gtid_excess_initial_delay.result

@@ -4,6 +4,8 @@ CREATE TABLE t1 (i INT);
 connection slave;
 include/stop_slave.inc
 CHANGE MASTER TO MASTER_USE_GTID= current_pos, MASTER_DELAY= 10;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection master;
 INSERT INTO t1 VALUES (1);

mysql-test/suite/rpl/r/rpl_gtid_master_promote.result

@@ -13,15 +13,23 @@ END|
 connection server_2;
 include/stop_slave.inc
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_3;
 include/stop_slave.inc
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_4;
 include/stop_slave.inc
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_5;
 include/stop_slave.inc
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_1;
 SET gtid_domain_id= 1;
 CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;
@@ -340,6 +348,8 @@ a	b
 connection server_1;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_2,
 master_user = "root", master_use_gtid = current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 SELECT * FROM t1 ORDER BY a;
 a

mysql-test/suite/rpl/r/rpl_gtid_mdev4473.result

@@ -13,6 +13,8 @@ reset slave all;
 connection server_1;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_2,
 master_user='root', MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 include/wait_for_slave_to_start.inc
 connection server_2;
@@ -23,6 +25,8 @@ flush logs;
 connection server_3;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_2,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 select * from t1 order by n;
 n
@@ -58,11 +62,15 @@ Note	4190	RESET SLAVE is implicitly changing the value of 'Using_Gtid' from 'Cur
 connection server_2;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_1,
 master_user = 'root', MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_3;
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_1,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_1;
 drop table t1;

mysql-test/suite/rpl/r/rpl_gtid_mdev4820.result

@@ -45,6 +45,8 @@ SET GLOBAL gtid_slave_pos= '0-2-10';
 connection server_1;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_2,
 master_user= 'root', master_use_gtid=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE;
 connection server_2;
 INSERT INTO t1 VALUES (11);
@@ -74,6 +76,8 @@ connection server_2;
 INSERT INTO t1 VALUES (22);
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_1,
 master_user= 'root', master_use_gtid=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE;
 SET sql_log_bin= 0;
 CALL mtr.add_suppression("which is not in the master's binlog. Since the master's binlog contains GTIDs with higher sequence numbers, it probably means that the slave has diverged");

mysql-test/suite/rpl/r/rpl_gtid_misc.result

@@ -10,6 +10,8 @@ SET sql_log_bin= 0;
 INSERT INTO t1 VALUES (1);
 SET sql_log_bin= 1;
 CHANGE MASTER TO master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection master;
 CREATE TEMPORARY TABLE t2 LIKE t1;
 INSERT INTO t2 VALUE (1);

mysql-test/suite/rpl/r/rpl_gtid_nobinlog.result

@@ -22,6 +22,8 @@ include/stop_slave.inc
 connection server_1;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SLAVE_PORT,
 master_user = 'root', master_use_gtid = current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE;
 include/wait_for_slave_to_start.inc
 connection server_2;
@@ -54,6 +56,8 @@ include/save_master_gtid.inc
 connection server_2;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 master_use_gtid = current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE;
 include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;

mysql-test/suite/rpl/r/rpl_gtid_reconnect.result

@@ -2,6 +2,8 @@ include/rpl_init.inc [topology=1->2]
 connection server_2;
 include/stop_slave.inc
 CHANGE MASTER TO master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_1;
 CREATE TABLE t1 (a INT);

mysql-test/suite/rpl/r/rpl_gtid_sort.result

@@ -59,6 +59,8 @@ Variable_name	Value
 gtid_binlog_state	
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 SHOW VARIABLES LIKE 'gtid_binlog_pos';
 Variable_name	Value

mysql-test/suite/rpl/r/rpl_gtid_startpos.result

@@ -12,6 +12,8 @@ connection server_2;
 SET GLOBAL gtid_slave_pos="";
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 SELECT * FROM t1;
 a
@@ -34,6 +36,8 @@ connection server_2;
 SET GLOBAL gtid_slave_pos="";
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE;
 include/wait_for_slave_io_error.inc [errno=1236]
 include/stop_slave.inc
@@ -56,6 +60,8 @@ connection server_2;
 SET GLOBAL gtid_slave_pos='0-1-3';
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER by a;
@@ -98,6 +104,8 @@ RESET MASTER;
 connection server_2;
 SET GLOBAL gtid_slave_pos='';
 CHANGE MASTER TO master_host='127.0.0.1', master_port=MASTER_PORT, master_user='root', master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_1;
 CREATE TABLE t1 (a INT PRIMARY KEY);
@@ -155,6 +163,8 @@ START SLAVE;
 include/wait_for_slave_sql_error.inc [errno=1050]
 STOP SLAVE IO_THREAD;
 CHANGE MASTER TO MASTER_USE_GTID=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_1;
 INSERT INTO t1 VALUES(3);

mysql-test/suite/rpl/r/rpl_gtid_stop_start.result

@@ -8,6 +8,8 @@ include/stop_slave.inc
 Master_Log_File = 'master-bin.000001'
 Using_Gtid = 'Slave_Pos'
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 FLUSH LOGS;
 connection server_1;
 FLUSH LOGS;

mysql-test/suite/rpl/r/rpl_gtid_until.result

@@ -30,6 +30,8 @@ include/stop_slave_io.inc
 START SLAVE UNTIL master_gtid_pos = "";
 ERROR HY000: START SLAVE UNTIL master_gtid_pos requires that slave is using GTID
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_1;
 CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;
 INSERT INTO t1 VALUES(1);
@@ -218,6 +220,8 @@ INSERT INTO t1 VALUES (10);
 connection server_2;
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_1,
 master_user = "root", master_use_gtid = current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 START SLAVE UNTIL master_gtid_pos = '0-1-2';
 include/wait_for_slave_to_start.inc
 connection server_1;

mysql-test/suite/rpl/r/rpl_mdev6386.result

@@ -11,6 +11,8 @@ CALL mtr.add_suppression("Commit failed due to failure of an earlier commit on w
 INSERT INTO t1 VALUES (1, 2);
 SET sql_log_bin= 1;
 CHANGE MASTER TO master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 Contents on slave before:
 SELECT * FROM t1 ORDER BY a;
 a	b

mysql-test/suite/rpl/r/rpl_parallel_mdev6589.result

@@ -5,6 +5,8 @@ SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
 include/stop_slave.inc
 SET GLOBAL slave_parallel_threads=10;
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 *** MDEV-6589: Incorrect relay log start position when restarting SQL thread after error in parallel replication ***
 connection server_1;

mysql-test/suite/rpl/r/rpl_parallel_multilevel2.result

@@ -18,11 +18,15 @@ SET @old_updates= @@GLOBAL.binlog_direct_non_transactional_updates;
 SET GLOBAL binlog_direct_non_transactional_updates=OFF;
 SET SESSION binlog_direct_non_transactional_updates=OFF;
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_3;
 SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
 include/stop_slave.inc
 SET GLOBAL slave_parallel_threads=10;
 CHANGE MASTER TO master_use_gtid=current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 connection server_1;
 BEGIN;
 CREATE TEMPORARY TABLE t2 (a INT PRIMARY KEY) ENGINE=MEMORY;

mysql-test/suite/rpl/r/rpl_parallel_temptable.result

@@ -5,6 +5,8 @@ SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
 include/stop_slave.inc
 SET GLOBAL slave_parallel_threads=5;
 CHANGE MASTER TO master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 connection server_1;
 CREATE TABLE t1 (a INT PRIMARY KEY, b VARCHAR(100) CHARACTER SET utf8);

mysql-test/suite/rpl/r/rpl_perfschema_connect_config.result

@@ -87,6 +87,8 @@ include/assert.inc [Value returned by SSS and PS table for Using_Gtid should be
 change master to
 master_user = 'root',
 master_use_gtid= CURRENT_POS;
+Warnings:
+Warning	####	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/assert.inc [Value returned by SSS and PS table for Using_Gtid should be same.]
 
 # 3) Test for Auto_position= SLAVE_POS

mysql-test/suite/rpl/r/rpl_start_alter_mysqlbinlog_1.result

@@ -5,6 +5,8 @@ set global binlog_alter_two_phase=true;
 connection slave;
 include/stop_slave.inc
 change master to master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 set global gtid_strict_mode=1;
 # Legacy Master Slave
 connect master_node,127.0.0.1,root,,$db_name, $M_port;

mysql-test/suite/rpl/r/rpl_start_alter_options.result

@@ -3,6 +3,8 @@ include/master-slave.inc
 connection slave;
 stop slave;
 change master to master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 SET GLOBAL slave_parallel_threads=4;
 set global slave_parallel_mode=optimistic;
 set global gtid_strict_mode=1;
@@ -94,6 +96,8 @@ include/start_slave.inc
 connection slave;
 stop slave;
 change master to master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 SET GLOBAL slave_parallel_threads=4;
 set global slave_parallel_mode=optimistic;
 set global gtid_strict_mode=1;
@@ -185,6 +189,8 @@ include/start_slave.inc
 connection slave;
 stop slave;
 change master to master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 SET GLOBAL slave_parallel_threads=4;
 set global slave_parallel_mode=optimistic;
 set global gtid_strict_mode=1;
@@ -315,6 +321,8 @@ include/start_slave.inc
 connection slave;
 stop slave;
 change master to master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 SET GLOBAL slave_parallel_threads=4;
 set global slave_parallel_mode=optimistic;
 set global gtid_strict_mode=1;
@@ -406,6 +414,8 @@ include/start_slave.inc
 connection slave;
 stop slave;
 change master to master_use_gtid= current_pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 SET GLOBAL slave_parallel_threads=4;
 set global slave_parallel_mode=optimistic;
 set global gtid_strict_mode=1;

mysql-test/suite/rpl/r/rpl_upgrade_master_info.result

@@ -4,6 +4,8 @@ include/master-slave.inc
 connection slave;
 include/stop_slave.inc
 CHANGE MASTER TO master_use_gtid=CURRENT_POS;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/rpl_stop_server.inc [server_number=2]
 include/rpl_start_server.inc [server_number=2]
 connection master;

mysql-test/suite/rpl/r/rpl_using_gtid_default.result

@@ -58,6 +58,8 @@ include/start_slave.inc
 # to its default of Slave_Pos after RESET SLAVE.
 include/stop_slave.inc
 CHANGE MASTER TO MASTER_USE_GTID=Current_Pos;
+Warnings:
+Warning	1681	'master_use_gtid=current_pos' is deprecated and will be removed in a future release. Please use master_demote_to_slave=1 instead
 include/start_slave.inc
 include/stop_slave.inc
 RESET SLAVE;

mysql-test/suite/rpl/t/rpl_change_master.test

@@ -108,4 +108,10 @@ CHANGE MASTER TO MASTER_USER='root', MASTER_SSL=0, MASTER_SSL_CA='', MASTER_SSL_
   MASTER_SSL_KEY='', MASTER_SSL_CRL='', MASTER_SSL_CRLPATH='';
 CHANGE MASTER TO MASTER_USER='root', MASTER_PASSWORD='', MASTER_SSL=0;
 
+
+# MDEV-20122: Deprecate MASTER_USE_GTID=Current_Pos to favor new MASTER_DEMOTE_TO_SLAVE option
+--echo "Usage of CURRENT_POS in CHANGE MASTER  MASTER_USE_GTID is dreprecated.
+CHANGE MASTER TO MASTER_USE_GTID=CURRENT_POS;
+CHANGE MASTER TO MASTER_USE_GTID=SLAVE_POS;
+
 --source include/rpl_end.inc

sql/lex.h

@@ -385,6 +385,7 @@ SYMBOL symbols[] = {
   { "MASTER_SSL_VERIFY_SERVER_CERT", SYM(MASTER_SSL_VERIFY_SERVER_CERT_SYM)},
   { "MASTER_USER",           SYM(MASTER_USER_SYM)},
   { "MASTER_USE_GTID",  SYM(MASTER_USE_GTID_SYM)},
+  { "MASTER_DEMOTE_TO_SLAVE",  SYM(MASTER_DEMOTE_TO_SLAVE_SYM)},
   { "MASTER_HEARTBEAT_PERIOD", SYM(MASTER_HEARTBEAT_PERIOD_SYM)},
   { "MATCH",		SYM(MATCH)},
   { "MAX_CONNECTIONS_PER_HOUR", SYM(MAX_CONNECTIONS_PER_HOUR)},

sql/rpl_mi.h

@@ -368,6 +368,14 @@ class Master_info : public Slave_reporting_capability
     Cache the value so future RESET SLAVE commands don't revert to Slave_Pos.
   */
   bool master_supports_gtid;
+
+  /*
+    When TRUE, transition this server from being an active master to a slave.
+    This updates the replication state to account for any transactions which
+    were committed into the binary log. In particular, it merges
+    gtid_binlog_pos into gtid_slave_pos.
+  */
+  bool is_demotion;
 };
 
 struct start_alter_thd_args

sql/sql_lex.h

@@ -498,6 +498,7 @@ struct LEX_MASTER_INFO
   uint port, connect_retry;
   float heartbeat_period;
   int sql_delay;
+  bool is_demotion_opt;
   /*
     Enum is used for making it possible to detect if the user
     changed variable or if it should be left at old value
@@ -540,6 +541,7 @@ struct LEX_MASTER_INFO
     gtid_pos_str= null_clex_str;
     use_gtid_opt= LEX_GTID_UNCHANGED;
     sql_delay= -1;
+    is_demotion_opt= 0;
   }
 };
 

sql/sql_repl.cc

@@ -3822,7 +3822,13 @@ bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
   if (lex_mi->use_gtid_opt == LEX_MASTER_INFO::LEX_GTID_SLAVE_POS)
     mi->using_gtid= Master_info::USE_GTID_SLAVE_POS;
   else if (lex_mi->use_gtid_opt == LEX_MASTER_INFO::LEX_GTID_CURRENT_POS)
+  {
     mi->using_gtid= Master_info::USE_GTID_CURRENT_POS;
+    push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
+                        ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT,
+                        ER_THD(thd, ER_WARN_DEPRECATED_SYNTAX),
+                        "master_use_gtid=current_pos", "master_demote_to_slave=1");
+  }
   else if (lex_mi->use_gtid_opt == LEX_MASTER_INFO::LEX_GTID_NO ||
            lex_mi->log_file_name || lex_mi->pos ||
            lex_mi->relay_log_name || lex_mi->relay_log_pos)
@@ -3913,6 +3919,40 @@ bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
      strmake_buf(mi->master_log_name, mi->rli.group_master_log_name);
   }
 
+  /*
+    MASTER_DEMOTE_TO_SLAVE is set. Merge gtid_binlog_pos into gtid_slave_pos.
+  */
+  if (lex_mi->is_demotion_opt)
+  {
+    String new_gtid_state;
+
+    if (mi->using_gtid != Master_info::USE_GTID_SLAVE_POS)
+    {
+      my_error(ER_CM_OPTION_MISSING_REQUIREMENT, MYF(0),
+               "MASTER_DEMOTE_TO_SLAVE", "TRUE", "Using_Gtid=Slave_Pos");
+      ret= TRUE;
+      goto err;
+    }
+
+    if (!mysql_bin_log.is_open())
+    {
+      my_error(ER_NO_BINARY_LOGGING, MYF(0));
+      ret= TRUE;
+      goto err;
+    }
+
+    if ((ret= rpl_append_gtid_state(&new_gtid_state, true)))
+      goto err;
+
+    if (rpl_global_gtid_slave_state->load(
+            thd, new_gtid_state.ptr(), new_gtid_state.length(), true, true))
+    {
+      my_error(ER_FAILED_GTID_STATE_INIT, MYF(0));
+      ret= TRUE;
+      goto err;
+    }
+  }
+
   /*
     Relay log's IO_CACHE may not be inited, if rli->inited==0 (server was never
     a slave before).

sql/sql_yacc.yy

@@ -936,6 +936,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  <kwd>  MASTER_USER_SYM
 %token  <kwd>  MASTER_USE_GTID_SYM
 %token  <kwd>  MASTER_HEARTBEAT_PERIOD_SYM
+%token  <kwd>  MASTER_DEMOTE_TO_SLAVE_SYM
 %token  <kwd>  MAX_CONNECTIONS_PER_HOUR
 %token  <kwd>  MAX_QUERIES_PER_HOUR
 %token  <kwd>  MAX_ROWS
@@ -2292,6 +2293,10 @@ master_file_def:
               my_yyabort_error((ER_DUP_ARGUMENT, MYF(0), "MASTER_use_gtid"));
             Lex->mi.use_gtid_opt= LEX_MASTER_INFO::LEX_GTID_NO;
           }
+        | MASTER_DEMOTE_TO_SLAVE_SYM '=' bool
+          {
+            Lex->mi.is_demotion_opt= (bool) $3;
+          }
         ;
 
 optional_connection_name: