MDEV-20601: Make REPLICA a synonym for SLAVE in SQL statements

Fix:
===
Add "REPLICA" as an alias for "SLAVE". All commands which use "SLAVE" keyword
can be used with new alias "REPLICA".

List of commands:

On Master:
=========
SHOW REPLICA HOSTS <--> SHOW SLAVE HOSTS
Privilege "SLAVE"  <--> "REPLICA"

On Slave:
=========
START SLAVE       <--> START REPLICA
START ALL SLAVES  <--> START ALL REPLICAS
START SLAVE UNTIL <--> START REPLICA UNTIL
STOP SLAVE        <--> STOP REPLICA
STOP ALL SLAVES   <--> STOP ALL REPLICAS
RESET SLAVE       <--> RESET REPLICA
RESET SLAVE ALL   <--> RESET REPLICA ALL
SLAVE_POS         <--> REPLICA_POS

2 files changed, 237 insertions, 0 deletions

diff --git a/mysql-test/suite/multi_source/multi_source_slave_alias_replica.result b/mysql-test/suite/multi_source/multi_source_slave_alias_replica.result
new file mode 100644
index 00000000000..de38313401d
--- /dev/null
+++ b/mysql-test/suite/multi_source/multi_source_slave_alias_replica.result
@@ -0,0 +1,157 @@
+connect  slave,127.0.0.1,root,,,$SERVER_MYPORT_3;
+connect  master1,127.0.0.1,root,,,$SERVER_MYPORT_1;
+connect  master2,127.0.0.1,root,,,$SERVER_MYPORT_2;
+connection slave;
+CHANGE MASTER 'slave1' TO MASTER_PORT=MYPORT_1, MASTER_HOST='127.0.0.1', MASTER_USER='root';
+CHANGE MASTER 'slave2' TO MASTER_PORT=MYPORT_2, MASTER_HOST='127.0.0.1', MASTER_USER='root';
+START REPLICA 'slave1';
+SET default_master_connection = 'slave1';
+include/wait_for_slave_to_start.inc
+SET default_master_connection = 'slave2';
+"Command: START ALL SLAVES --> START ALL REPLICAS"
+START ALL REPLICAS;
+Warnings:
+Note	1937	SLAVE 'slave2' started
+include/wait_for_slave_to_start.inc
+SET default_master_connection = '';
+connection master1;
+connection slave;
+connection master2;
+connection slave;
+"Command: SHOW ALL STAVES STATUS --> SHOW ALL REPLICAS STATUS"
+SHOW ALL REPLICAS STATUS;
+Connection_name	slave1
+Slave_SQL_State	Slave has read all relay log; waiting for the slave I/O thread to update it
+Slave_IO_State	Waiting for master to send event
+Master_Host	127.0.0.1
+Master_User	root
+Master_Port	MYPORT_1
+Connect_Retry	60
+Master_Log_File	master-bin.000001
+Read_Master_Log_Pos	<read_master_log_pos>
+Relay_Log_File	mysqld-relay-bin-slave1.000002
+Relay_Log_Pos	<relay_log_pos>
+Relay_Master_Log_File	master-bin.000001
+Slave_IO_Running	Yes
+Slave_SQL_Running	Yes
+Replicate_Do_DB	
+Replicate_Ignore_DB	
+Replicate_Do_Table	
+Replicate_Ignore_Table	
+Replicate_Wild_Do_Table	
+Replicate_Wild_Ignore_Table	
+Last_Errno	0
+Last_Error	
+Skip_Counter	0
+Exec_Master_Log_Pos	<read_master_log_pos>
+Relay_Log_Space	<relay_log_space1>
+Until_Condition	None
+Until_Log_File	
+Until_Log_Pos	0
+Master_SSL_Allowed	No
+Master_SSL_CA_File	
+Master_SSL_CA_Path	
+Master_SSL_Cert	
+Master_SSL_Cipher	
+Master_SSL_Key	
+Seconds_Behind_Master	0
+Master_SSL_Verify_Server_Cert	No
+Last_IO_Errno	0
+Last_IO_Error	
+Last_SQL_Errno	0
+Last_SQL_Error	
+Replicate_Ignore_Server_Ids	
+Master_Server_Id	1
+Master_SSL_Crl	
+Master_SSL_Crlpath	
+Using_Gtid	No
+Gtid_IO_Pos	
+Replicate_Do_Domain_Ids	
+Replicate_Ignore_Domain_Ids	
+Parallel_Mode	optimistic
+SQL_Delay	0
+SQL_Remaining_Delay	NULL
+Slave_SQL_Running_State	Slave has read all relay log; waiting for the slave I/O thread to update it
+Slave_DDL_Groups	0
+Slave_Non_Transactional_Groups	0
+Slave_Transactional_Groups	0
+Retried_transactions	0
+Max_relay_log_size	1073741824
+Executed_log_entries	7
+Slave_received_heartbeats	0
+Slave_heartbeat_period	60.000
+Gtid_Slave_Pos	
+Connection_name	slave2
+Slave_SQL_State	Slave has read all relay log; waiting for the slave I/O thread to update it
+Slave_IO_State	Waiting for master to send event
+Master_Host	127.0.0.1
+Master_User	root
+Master_Port	MYPORT_2
+Connect_Retry	60
+Master_Log_File	master-bin.000001
+Read_Master_Log_Pos	<read_master_log_pos>
+Relay_Log_File	mysqld-relay-bin-slave2.000002
+Relay_Log_Pos	<relay_log_pos>
+Relay_Master_Log_File	master-bin.000001
+Slave_IO_Running	Yes
+Slave_SQL_Running	Yes
+Replicate_Do_DB	
+Replicate_Ignore_DB	
+Replicate_Do_Table	
+Replicate_Ignore_Table	
+Replicate_Wild_Do_Table	
+Replicate_Wild_Ignore_Table	
+Last_Errno	0
+Last_Error	
+Skip_Counter	0
+Exec_Master_Log_Pos	<read_master_log_pos>
+Relay_Log_Space	<relay_log_space1>
+Until_Condition	None
+Until_Log_File	
+Until_Log_Pos	0
+Master_SSL_Allowed	No
+Master_SSL_CA_File	
+Master_SSL_CA_Path	
+Master_SSL_Cert	
+Master_SSL_Cipher	
+Master_SSL_Key	
+Seconds_Behind_Master	0
+Master_SSL_Verify_Server_Cert	No
+Last_IO_Errno	0
+Last_IO_Error	
+Last_SQL_Errno	0
+Last_SQL_Error	
+Replicate_Ignore_Server_Ids	
+Master_Server_Id	2
+Master_SSL_Crl	
+Master_SSL_Crlpath	
+Using_Gtid	No
+Gtid_IO_Pos	
+Replicate_Do_Domain_Ids	
+Replicate_Ignore_Domain_Ids	
+Parallel_Mode	optimistic
+SQL_Delay	0
+SQL_Remaining_Delay	NULL
+Slave_SQL_Running_State	Slave has read all relay log; waiting for the slave I/O thread to update it
+Slave_DDL_Groups	0
+Slave_Non_Transactional_Groups	0
+Slave_Transactional_Groups	0
+Retried_transactions	0
+Max_relay_log_size	1073741824
+Executed_log_entries	7
+Slave_received_heartbeats	0
+Slave_heartbeat_period	60.000
+Gtid_Slave_Pos	
+"Command: STOP ALL SLAVES --> STOP ALL REPLICAS"
+STOP ALL REPLICAS;
+Warnings:
+Note	1938	SLAVE 'slave2' stopped
+Note	1938	SLAVE 'slave1' stopped
+include/reset_master_slave.inc
+disconnect slave;
+connection master1;
+include/reset_master_slave.inc
+disconnect master1;
+connection master2;
+include/reset_master_slave.inc
+disconnect master2;
diff --git a/mysql-test/suite/multi_source/multi_source_slave_alias_replica.test b/mysql-test/suite/multi_source/multi_source_slave_alias_replica.test
new file mode 100644
index 00000000000..409718dd4e7
--- /dev/null
+++ b/mysql-test/suite/multi_source/multi_source_slave_alias_replica.test
@@ -0,0 +1,80 @@
+# ==== Purpose ====
+#
+# Test verifies that SQL statements which use keyword 'REPLICA' a synonym for
+# 'SLAVE' work as expected.
+#
+# ==== Implementation ====
+#
+# List of commands being verified are
+#
+# START ALL REPLICAS
+# STOP ALL REPLICAS
+# SHOW ALL REPLICAS STATUS
+#
+# ==== References ====
+#
+# MDEV-20601: Make REPLICA a synonym for SLAVE in SQL statements
+#
+
+--source include/not_embedded.inc
+--source include/binlog_start_pos.inc
+--let $rpl_server_count= 0
+
+--connect (slave,127.0.0.1,root,,,$SERVER_MYPORT_3)
+--connect (master1,127.0.0.1,root,,,$SERVER_MYPORT_1)
+--connect (master2,127.0.0.1,root,,,$SERVER_MYPORT_2)
+
+--connection slave
+--replace_result $SERVER_MYPORT_1 MYPORT_1
+eval CHANGE MASTER 'slave1' TO MASTER_PORT=$SERVER_MYPORT_1, MASTER_HOST='127.0.0.1', MASTER_USER='root';
+--replace_result $SERVER_MYPORT_2 MYPORT_2
+eval CHANGE MASTER 'slave2' TO MASTER_PORT=$SERVER_MYPORT_2, MASTER_HOST='127.0.0.1', MASTER_USER='root';
+START REPLICA 'slave1';
+SET default_master_connection = 'slave1';
+--source include/wait_for_slave_to_start.inc
+SET default_master_connection = 'slave2';
+--echo "Command: START ALL SLAVES --> START ALL REPLICAS"
+START ALL REPLICAS;
+
+--source include/wait_for_slave_to_start.inc
+SET default_master_connection = '';
+
+# Ensure that all data is in the relay log
+--connection master1
+--save_master_pos
+--connection slave
+--sync_with_master 0,'slave1'
+--connection master2
+--save_master_pos
+--connection slave
+--sync_with_master 0,'slave2'
+
+--echo "Command: SHOW ALL STAVES STATUS --> SHOW ALL REPLICAS STATUS"
+let $show_statement = SHOW ALL REPLICAS STATUS;
+let $field = Executed_log_entries;
+let $condition = = 7;
+let $wait_for_all = 1;
+--source include/wait_show_condition.inc
+
+let read_master_log_pos=`select $binlog_start_pos + 73`;
+let relay_log_pos=`select 2*$binlog_start_pos + 117`;
+let relay_log_space1=`select 3*$binlog_start_pos + 178`;
+let relay_log_space2=`select 3*$binlog_start_pos + 178`;
+--replace_result $SERVER_MYPORT_1 MYPORT_1 $SERVER_MYPORT_2 MYPORT_2 $read_master_log_pos <read_master_log_pos> $relay_log_pos <relay_log_pos> $relay_log_space1 <relay_log_space1> $relay_log_space2 <relay_log_space2>
+--query_vertical SHOW ALL REPLICAS STATUS
+
+--echo "Command: STOP ALL SLAVES --> STOP ALL REPLICAS"
+STOP ALL REPLICAS;
+
+#
+# clean up
+#
+
+--source include/reset_master_slave.inc
+--disconnect slave
+--connection master1
+--source include/reset_master_slave.inc
+--disconnect master1
+--connection master2
+--source include/reset_master_slave.inc
+--disconnect master2