Merge of MDEV-4984, MDEV-4726, and MDEV-5636 into 10.0-base.

MDEV-4984: Implement MASTER_GTID_WAIT() and @@LAST_GTID. MDEV-4726: Race in mysql-test/suite/rpl/t/rpl_gtid_stop_start.test MDEV-5636: Deadlock in RESET MASTER
2014-02-10 12:39:26 +01:00 · 2014-02-10 12:39:26 +01:00 · fefdb576bb
commit fefdb576bb
parent 8cc6e90d74 4a976545e5
38 changed files with 1283 additions and 110 deletions
--- a/client/mysql.cc
+++ b/client/mysql.cc
@ -915,6 +915,7 @@ static COMMANDS commands[] = {
  { "MAKE_SET", 0, 0, 0, ""},
  { "MAKEDATE", 0, 0, 0, ""},
  { "MAKETIME", 0, 0, 0, ""},
+  { "MASTER_GTID_WAIT", 0, 0, 0, ""},
  { "MASTER_POS_WAIT", 0, 0, 0, ""},
  { "MAX", 0, 0, 0, ""},
  { "MBRCONTAINS", 0, 0, 0, ""},
--- a/include/queues.h
+++ b/include/queues.h
@ -51,6 +51,7 @@ typedef struct st_queue {

 #define queue_first_element(queue) 1
 #define queue_last_element(queue) (queue)->elements
+#define queue_empty(queue) ((queue)->elements == 0)
 #define queue_top(queue) ((queue)->root[1])
 #define queue_element(queue,index) ((queue)->root[index])
 #define queue_end(queue) ((queue)->root[(queue)->elements])
--- a/mysql-test/include/save_master_gtid.inc
+++ b/mysql-test/include/save_master_gtid.inc
@ -0,0 +1,28 @@
+# ==== Purpose ====
+#
+# Save the current binlog GTID position on the master, to be used
+# with include/sync_with_master_gtid.inc.
+#
+#
+# ==== Usage ====
+#
+# [--let $rpl_debug= 1]
+# --source include/save_master_gtid.inc
+#
+# Parameters:
+#   $rpl_debug
+#     See include/rpl_init.inc
+
+
+--let $include_filename= save_master_gtid.inc
+--source include/begin_include_file.inc
+
+--let $master_pos= `SELECT @@gtid_binlog_pos`
+
+if ($rpl_debug)
+{
+  --echo save_master_gtid saved master_pos='$master_pos'
+}
+
+--let $include_filename= save_master_gtid.inc
+--source include/end_include_file.inc
--- a/mysql-test/include/sync_with_master_gtid.inc
+++ b/mysql-test/include/sync_with_master_gtid.inc
@ -0,0 +1,48 @@
+# ==== Purpose ====
+#
+# Wait until the slave has reached a certain GTID position.
+# Similar to --sync_with_master, but using GTID instead of old-style
+# binlog file/offset coordinates.
+#
+#
+# ==== Usage ====
+#
+# --let $master_pos= `SELECT @@GLOBAL.gtid_binlog_pos`
+# [--let $slave_timeout= NUMBER]
+# [--let $rpl_debug= 1]
+# --source include/sync_with_master_gtid.inc
+#
+# Syncs slave to the specified GTID position.
+#
+# Must be called on the slave.
+#
+# Parameters:
+#   $master_pos
+#     The GTID position to sync to. Typically obtained from
+#      @@GLOBAL.gtid_binlog_pos on the master.
+#
+#   $slave_timeout
+#      Timeout in seconds. The default is 2 minutes.
+#
+#   $rpl_debug
+#      See include/rpl_init.inc
+
+--let $include_filename= sync_with_master_gtid.inc
+--source include/begin_include_file.inc
+
+let $_slave_timeout= $slave_timeout;
+if (!$_slave_timeout)
+{
+  let $_slave_timeout= 120;
+}
+
+--let $_result= `SELECT master_gtid_wait('$master_pos', $_slave_timeout)`
+if ($_result == -1)
+{
+  --let $_current_gtid_pos= `SELECT @@GLOBAL.gtid_slave_pos`
+  --echo Timeout in master_gtid_wait('$master_pos', $_slave_timeout), current slave GTID position is: $_current_gtid_pos.
+  --die Failed to sync with master
+}
+
+--let $include_filename= sync_with_master_gtid.inc
+--source include/end_include_file.inc
--- a/mysql-test/suite/perfschema/r/all_instances.result
+++ b/mysql-test/suite/perfschema/r/all_instances.result
@ -37,6 +37,7 @@ wait/synch/mutex/mysys/THR_LOCK_threads
 wait/synch/mutex/mysys/TMPDIR_mutex
 wait/synch/mutex/sql/Cversion_lock
 wait/synch/mutex/sql/Event_scheduler::LOCK_scheduler_state
+wait/synch/mutex/sql/gtid_waiting::LOCK_gtid_waiting
 wait/synch/mutex/sql/hash_filo::lock
 wait/synch/mutex/sql/LOCK_active_mi
 wait/synch/mutex/sql/LOCK_audit_mask
--- a/mysql-test/suite/perfschema/r/dml_setup_instruments.result
+++ b/mysql-test/suite/perfschema/r/dml_setup_instruments.result
@ -7,13 +7,13 @@ NAME	ENABLED	TIMED
 wait/synch/mutex/sql/Cversion_lock	YES	YES
 wait/synch/mutex/sql/Delayed_insert::mutex	YES	YES
 wait/synch/mutex/sql/Event_scheduler::LOCK_scheduler_state	YES	YES
+wait/synch/mutex/sql/gtid_waiting::LOCK_gtid_waiting	YES	YES
 wait/synch/mutex/sql/hash_filo::lock	YES	YES
 wait/synch/mutex/sql/HA_DATA_PARTITION::LOCK_auto_inc	YES	YES
 wait/synch/mutex/sql/LOCK_active_mi	YES	YES
 wait/synch/mutex/sql/LOCK_audit_mask	YES	YES
 wait/synch/mutex/sql/LOCK_binlog_state	YES	YES
 wait/synch/mutex/sql/LOCK_commit_ordered	YES	YES
-wait/synch/mutex/sql/LOCK_connection_count	YES	YES
 select * from performance_schema.setup_instruments
 where name like 'Wait/Synch/Rwlock/sql/%'
  and name not in ('wait/synch/rwlock/sql/CRYPTO_dynlock_value::lock')
--- a/mysql-test/suite/rpl/r/rpl_gtid_basic.result
+++ b/mysql-test/suite/rpl/r/rpl_gtid_basic.result
@ -99,13 +99,13 @@ a	b
 5	j1a
 *** Now move C to D, after letting it fall a little behind ***
 include/stop_slave.inc
-BEGIN;
 INSERT INTO t2 VALUES (6, "i6b");
 INSERT INTO t2 VALUES (7, "i7b");
-COMMIT;
+include/save_master_gtid.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_4,
 MASTER_USE_GTID=CURRENT_POS;
 include/start_slave.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t2 ORDER BY a;
 a	b
 1	i1
@ -116,6 +116,7 @@ a	b
 6	i6b
 7	i7b
 *** Now change everything back to what it was, to make rpl_end.inc happy
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_MYPORT;
 include/start_slave.inc
@ -123,10 +124,12 @@ include/wait_for_slave_to_start.inc
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SLAVE_MYPORT;
 include/start_slave.inc
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SERVER_MYPORT_3;
 include/start_slave.inc
 DROP TABLE t1,t2;
+include/save_master_gtid.inc
 *** A few more checks for BINLOG_GTID_POS function ***
 SELECT BINLOG_GTID_POS();
 ERROR 42000: Incorrect parameter count in the call to native function 'BINLOG_GTID_POS'
@ -163,6 +166,7 @@ NULL
 Warnings:
 Warning	1916	Got overflow when converting '18446744073709551616' to INT. Value truncated.
 *** Some tests of @@GLOBAL.gtid_binlog_state ***
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 SET @old_state= @@GLOBAL.gtid_binlog_state;
 SET GLOBAL gtid_binlog_state = '';
@ -196,10 +200,121 @@ SET GLOBAL gtid_binlog_state = @old_state;
 CREATE TABLE t1 (a INT PRIMARY KEY);
 SET gtid_seq_no=100;
 INSERT INTO t1 VALUES (1);
+include/save_master_gtid.inc
 include/start_slave.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1;
 a
 1
 Gtid_IO_Pos = '0-1-100'
+*** Test @@LAST_GTID and MASTER_GTID_WAIT() ***
+DROP TABLE t1;
+CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;
+include/stop_slave.inc
+SELECT @@last_gtid;
+@@last_gtid
+
+SET gtid_seq_no=110;
+SELECT @@last_gtid;
+@@last_gtid
+
+BEGIN;
+SELECT @@last_gtid;
+@@last_gtid
+
+INSERT INTO t1 VALUES (2);
+SELECT @@last_gtid;
+@@last_gtid
+
+COMMIT;
+SELECT @@last_gtid;
+@@last_gtid
+0-1-110
+SET @pos= '0-1-110';
+SELECT master_gtid_wait(NULL);
+master_gtid_wait(NULL)
+NULL
+SELECT master_gtid_wait('', NULL);
+master_gtid_wait('', NULL)
+0
+SELECT master_gtid_wait(@pos, 0.5);
+master_gtid_wait(@pos, 0.5)
+-1
+SELECT * FROM t1 ORDER BY a;
+a
+SELECT master_gtid_wait(@pos);
+include/start_slave.inc
+master_gtid_wait(@pos)
+0
+SELECT * FROM t1 ORDER BY a;
+a
+2
+include/stop_slave.inc
+SET gtid_domain_id= 1;
+INSERT INTO t1 VALUES (3);
+SET @pos= '1-1-1,0-1-110';
+SELECT master_gtid_wait(@pos, 0);
+master_gtid_wait(@pos, 0)
+-1
+SELECT * FROM t1 WHERE a >= 3;
+a
+SELECT master_gtid_wait(@pos, -1);
+include/start_slave.inc
+master_gtid_wait(@pos, -1)
+0
+SELECT * FROM t1 WHERE a >= 3;
+a
+3
+SELECT master_gtid_wait('1-1-1', 0);
+master_gtid_wait('1-1-1', 0)
+0
+SELECT master_gtid_wait('2-1-1,1-1-4,0-1-110');
+SELECT master_gtid_wait('0-1-1000', 0.5);
+SELECT master_gtid_wait('0-1-2000');
+SELECT master_gtid_wait('2-1-10');
+SELECT master_gtid_wait('2-1-6', 1);
+SELECT master_gtid_wait('2-1-5');
+SELECT master_gtid_wait('2-1-10');
+SELECT master_gtid_wait('2-1-5,1-1-4,0-1-110');
+SELECT master_gtid_wait('2-1-2');
+SELECT master_gtid_wait('1-1-1');
+master_gtid_wait('1-1-1')
+0
+SELECT master_gtid_wait('0-1-109');
+SELECT master_gtid_wait('2-1-2', 0.5);
+master_gtid_wait('2-1-2', 0.5)
+-1
+KILL QUERY KILL_ID;
+ERROR 70100: Query execution was interrupted
+SET gtid_domain_id=2;
+SET gtid_seq_no=2;
+INSERT INTO t1 VALUES (4);
+master_gtid_wait('2-1-2')
+0
+KILL CONNECTION KILL_ID;
+ERROR HY000: Lost connection to MySQL server during query
+SET gtid_domain_id=1;
+SET gtid_seq_no=4;
+INSERT INTO t1 VALUES (5);
+SET gtid_domain_id=2;
+SET gtid_seq_no=5;
+INSERT INTO t1 VALUES (6);
+master_gtid_wait('2-1-5,1-1-4,0-1-110')
+0
+master_gtid_wait('2-1-1,1-1-4,0-1-110')
+0
+master_gtid_wait('0-1-1000', 0.5)
+-1
+master_gtid_wait('2-1-6', 1)
+-1
+master_gtid_wait('0-1-109')
+0
+SET gtid_domain_id=2;
+SET gtid_seq_no=10;
+INSERT INTO t1 VALUES (7);
+master_gtid_wait('2-1-10')
+0
+master_gtid_wait('2-1-10')
+0
 DROP TABLE t1;
 include/rpl_end.inc
--- a/mysql-test/suite/rpl/r/rpl_gtid_crash.result
+++ b/mysql-test/suite/rpl/r/rpl_gtid_crash.result
@ -12,10 +12,14 @@ MASTER_USE_GTID=CURRENT_POS;
 INSERT INTO t1 VALUES (2,1);
 INSERT INTO t1 VALUES (3,1);
 include/start_slave.inc
+include/save_master_gtid.inc
 SET SESSION debug_dbug="+d,crash_dispatch_command_before";
 SELECT 1;
 Got one of the listed errors
+include/sync_with_master_gtid.inc
 INSERT INTO t1 VALUES (1000, 3);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 DROP TABLE t1;
 *** Test crashing the master mysqld and check that binlog state is recovered. ***
 include/stop_slave.inc
@ -64,22 +68,32 @@ include/stop_slave.inc
 SET GLOBAL debug_dbug="+d,inject_crash_before_write_rpl_slave_state";
 START SLAVE;
 INSERT INTO t1 VALUES (4);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 SET GLOBAL debug_dbug="+d,crash_commit_before";
 START SLAVE;
 INSERT INTO t1 VALUES (5);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 SET GLOBAL debug_dbug="+d,crash_commit_after";
 START SLAVE;
 INSERT INTO t1 VALUES (6);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 SET GLOBAL debug_dbug="+d,inject_crash_before_flush_rli";
 START SLAVE;
 INSERT INTO t1 VALUES (7);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 SET GLOBAL debug_dbug="+d,inject_crash_after_flush_rli";
 START SLAVE;
 INSERT INTO t1 VALUES (8);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
--- a/mysql-test/suite/rpl/r/rpl_gtid_errorhandling.result
+++ b/mysql-test/suite/rpl/r/rpl_gtid_errorhandling.result
@ -57,6 +57,7 @@ include/stop_slave.inc
 RESET MASTER;
 INSERT INTO t1 VALUES (2);
 INSERT INTO t1 VALUES (4);
+include/save_master_gtid.inc
 SET sql_log_bin = 0;
 INSERT INTO t1 VALUES (2);
 SET sql_log_bin = 1;
@ -84,6 +85,7 @@ Warning	1948	Specified value for @@gtid_slave_pos contains no value for replicat
 RESET MASTER;
 SET GLOBAL gtid_slave_pos = "0-1-1";
 START SLAVE;
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
@ -93,6 +95,7 @@ a
 *** MDEV-4688: Empty value of @@GLOBAL.gtid_slave_pos ***
 include/stop_slave.inc
 INSERT INTO t1 VALUES (5);
+include/save_master_gtid.inc
 SET @old_dbug= @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug="+d,dummy_disable_default_dbug_output";
 SET GLOBAL debug_dbug="+d,gtid_fail_after_record_gtid";
@ -112,6 +115,7 @@ a
 4
 SET GLOBAL debug_dbug= @old_dbug;
 START SLAVE SQL_THREAD;
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
@ -136,6 +140,8 @@ SET GLOBAL gtid_slave_pos = "0-1-3";
 START SLAVE;
 include/wait_for_slave_to_start.inc
 INSERT INTO t1 VALUES (6);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
--- a/mysql-test/suite/rpl/r/rpl_gtid_nobinlog.result
+++ b/mysql-test/suite/rpl/r/rpl_gtid_nobinlog.result
@ -23,6 +23,7 @@ START SLAVE;
 include/wait_for_slave_to_start.inc
 INSERT INTO t1 VALUES (3, 2);
 INSERT INTO t1 VALUES (4, 2);
+include/save_master_gtid.inc
 show binlog events from <binlog_start>;
 Log_name	Pos	Event_type	Server_id	End_log_pos	Info
 slave-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
@ -31,6 +32,7 @@ slave-bin.000001	#	Query	#	#	COMMIT
 slave-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
 slave-bin.000001	#	Query	#	#	use `test`; INSERT INTO t1 VALUES (4, 2)
 slave-bin.000001	#	Query	#	#	COMMIT
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a	b
 1	1
@ -41,9 +43,11 @@ include/stop_slave.inc
 RESET SLAVE;
 INSERT INTO t1 VALUES (5, 1);
 INSERT INTO t1 VALUES (6, 1);
+include/save_master_gtid.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT,
 master_use_gtid = current_pos;
 START SLAVE;
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a	b
 1	1
--- a/mysql-test/suite/rpl/r/rpl_gtid_startpos.result
+++ b/mysql-test/suite/rpl/r/rpl_gtid_startpos.result
@ -43,10 +43,12 @@ SET sql_log_bin=1;
 *** Test that we give warning when explict @@gtid_slave_pos=xxx that conflicts with what is in our binary log ***
 include/stop_slave.inc
 INSERT INTO t1 VALUES(3);
+include/save_master_gtid.inc
 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;
 include/start_slave.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER by a;
 a
 1
@ -54,6 +56,7 @@ a
 3
 include/stop_slave.inc
 INSERT INTO t1 VALUES (4);
+include/save_master_gtid.inc
 INSERT INTO t1 VALUES (10);
 DELETE FROM t1 WHERE a=10;
 SET GLOBAL gtid_slave_pos='0-1-4';
@ -62,6 +65,7 @@ Warning	1947	Specified GTID 0-1-4 conflicts with the binary log which contains a
 RESET MASTER;
 SET GLOBAL gtid_slave_pos='0-1-4';
 START SLAVE;
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER by a;
 a
 1
@ -125,6 +129,8 @@ STOP SLAVE IO_THREAD;
 CHANGE MASTER TO MASTER_USE_GTID=CURRENT_POS;
 include/start_slave.inc
 INSERT INTO t1 VALUES(3);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
@ -136,6 +142,8 @@ SET SQL_LOG_BIN=1;
 *** Test reconnecting slave with GTID after purge logs on master. ***
 FLUSH LOGS;
 INSERT INTO t1 VALUES (4);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 include/stop_slave.inc
 FLUSH LOGS;
 FLUSH LOGS;
@ -144,8 +152,10 @@ show binary logs;
 Log_name	File_size
 master-bin.000004	#
 INSERT INTO t1 VALUES (5);
+include/save_master_gtid.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_PORT;
 include/start_slave.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
@ -160,7 +170,9 @@ SET GLOBAL gtid_slave_pos="";
 RESET MASTER;
 TRUNCATE TABLE t1;
 INSERT INTO t1 VALUES (10);
+include/save_master_gtid.inc
 include/start_slave.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1;
 a
 10
--- a/mysql-test/suite/rpl/r/rpl_gtid_stop_start.result
+++ b/mysql-test/suite/rpl/r/rpl_gtid_stop_start.result
@ -14,10 +14,12 @@ master-bin.000002	#
 INSERT INTO t1 VALUES (2);
 FLUSH LOGS;
 INSERT INTO t1 VALUES (3);
+include/save_master_gtid.inc
 show binary logs;
 Log_name	File_size
 master-bin.000002	#
 master-bin.000003	#
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
@ -43,6 +45,8 @@ master-bin.000003	#
 master-bin.000004	#
 master-bin.000005	#
 INSERT INTO t1 VALUES(5);
+include/save_master_gtid.inc
+include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 a
 1
--- a/mysql-test/suite/rpl/t/rpl_gtid_basic.test
+++ b/mysql-test/suite/rpl/t/rpl_gtid_basic.test
@ -97,19 +97,16 @@ connection server_3;
 --source include/stop_slave.inc

 connection server_1;
-BEGIN;
 INSERT INTO t2 VALUES (6, "i6b");
 INSERT INTO t2 VALUES (7, "i7b");
-COMMIT;
+--source include/save_master_gtid.inc

 connection server_3;
 --replace_result $SERVER_MYPORT_4 SERVER_MYPORT_4
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $SERVER_MYPORT_4,
     MASTER_USE_GTID=CURRENT_POS;
 --source include/start_slave.inc
-# This time, let's sync up without reference to binlog on D.
--let $wait_condition= SELECT COUNT(*) = 7 FROM t2
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t2 ORDER BY a;

 --echo *** Now change everything back to what it was, to make rpl_end.inc happy
@ -118,8 +115,7 @@ connection server_2;
 # We need to sync up server_2 before switching. If it happened to have reached
 # the point 'UPDATE t2 SET b="j1a" WHERE a=5' it will fail to connect to
 # server_1, which is (deliberately) missing that transaction.
--let $wait_condition= SELECT COUNT(*) = 7 FROM t2
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 --source include/stop_slave.inc
 --replace_result $MASTER_MYPORT MASTER_MYPORT
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $MASTER_MYPORT;
@ -131,8 +127,7 @@ connection server_3;
 --replace_result $SLAVE_MYPORT SLAVE_MYPORT
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $SLAVE_MYPORT;
 --source include/start_slave.inc
--let $wait_condition= SELECT COUNT(*) = 7 FROM t2
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 connection server_4;
 --source include/stop_slave.inc
@ -142,6 +137,7 @@ eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $SERVER_MYPORT_3;

 connection server_1;
 DROP TABLE t1,t2;
+--source include/save_master_gtid.inc

 --echo *** A few more checks for BINLOG_GTID_POS function ***
 --let $valid_binlog_name = query_get_value(SHOW BINARY LOGS,Log_name,1)
@ -163,6 +159,7 @@ eval SELECT BINLOG_GTID_POS('$valid_binlog_name',18446744073709551616);

 --echo *** Some tests of @@GLOBAL.gtid_binlog_state ***
 --connection server_2
+--source include/sync_with_master_gtid.inc
 --source include/stop_slave.inc

 --connection server_1
@ -192,21 +189,183 @@ SET GLOBAL gtid_binlog_state = @old_state;
 CREATE TABLE t1 (a INT PRIMARY KEY);
 SET gtid_seq_no=100;
 INSERT INTO t1 VALUES (1);
--let $master_pos= `SELECT @@GLOBAL.gtid_binlog_pos`
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/start_slave.inc
 # We cannot just use sync_with_master as we've done RESET MASTER, so
 # slave old-style position is wrong.
 # So sync on gtid position instead.
--let $wait_condition= SELECT @@GLOBAL.gtid_binlog_pos = '$master_pos'
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 SELECT * FROM t1;
 # Check that the IO gtid position in SHOW SLAVE STATUS is also correct.
 --let $status_items= Gtid_IO_Pos
 --source include/show_slave_status.inc

+--echo *** Test @@LAST_GTID and MASTER_GTID_WAIT() ***
+
+--connection server_1
+DROP TABLE t1;
+CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;
+--save_master_pos
+
+--connection server_2
+--sync_with_master
+--source include/stop_slave.inc
+
+--connect (m1,127.0.0.1,root,,test,$SERVER_MYPORT_1,)
+SELECT @@last_gtid;
+SET gtid_seq_no=110;
+SELECT @@last_gtid;
+BEGIN;
+SELECT @@last_gtid;
+INSERT INTO t1 VALUES (2);
+SELECT @@last_gtid;
+COMMIT;
+SELECT @@last_gtid;
+--let $pos= `SELECT @@gtid_binlog_pos`
+
+--connect (s1,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+eval SET @pos= '$pos';
+# Check NULL argument.
+SELECT master_gtid_wait(NULL);
+# Check empty argument returns immediately.
+SELECT master_gtid_wait('', NULL);
+# Let's check that we get a timeout
+SELECT master_gtid_wait(@pos, 0.5);
+SELECT * FROM t1 ORDER BY a;
+# Now actually wait until the slave reaches the position
+send SELECT master_gtid_wait(@pos);
+
+--connection server_2
+--source include/start_slave.inc
+
+--connection s1
+reap;
+SELECT * FROM t1 ORDER BY a;
+
+# Test waiting on a domain that does not exist yet.
+--source include/stop_slave.inc
+
+--connection server_1
+SET gtid_domain_id= 1;
+INSERT INTO t1 VALUES (3);
+--let $pos= `SELECT @@gtid_binlog_pos`
+
+--connection s1
+eval SET @pos= '$pos';
+SELECT master_gtid_wait(@pos, 0);
+SELECT * FROM t1 WHERE a >= 3;
+send SELECT master_gtid_wait(@pos, -1);
+
+--connection server_2
+--source include/start_slave.inc
+
+--connection s1
+reap;
+SELECT * FROM t1 WHERE a >= 3;
+# Waiting for only part of the position.
+SELECT master_gtid_wait('1-1-1', 0);
+
+# Now test a lot of parallel master_gtid_wait() calls, completing in different
+# order, and some of which time out or get killed on the way.
+
+--connection s1
+send SELECT master_gtid_wait('2-1-1,1-1-4,0-1-110');
+
+--connect (s2,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+# This will time out.
+send SELECT master_gtid_wait('0-1-1000', 0.5);
+
+--connect (s3,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+# This one we will kill
+--let $kill1_id= `SELECT connection_id()`
+send SELECT master_gtid_wait('0-1-2000');
+
+--connect (s4,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+send SELECT master_gtid_wait('2-1-10');
+
+--connect (s5,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+send SELECT master_gtid_wait('2-1-6', 1);
+
+# This one we will kill also.
+--connect (s6,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+--let $kill2_id= `SELECT connection_id()`
+send SELECT master_gtid_wait('2-1-5');
+
+--connect (s7,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+send SELECT master_gtid_wait('2-1-10');
+
+--connect (s8,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+send SELECT master_gtid_wait('2-1-5,1-1-4,0-1-110');
+
+--connect (s9,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+send SELECT master_gtid_wait('2-1-2');
+
+--connection server_2
+# This one completes immediately.
+SELECT master_gtid_wait('1-1-1');
+
+--connect (s10,127.0.0.1,root,,test,$SERVER_MYPORT_2,)
+send SELECT master_gtid_wait('0-1-109');
+
+--connection server_2
+# This one should time out.
+SELECT master_gtid_wait('2-1-2', 0.5);
+
+--replace_result $kill1_id KILL_ID
+eval KILL QUERY $kill1_id;
+--connection s3
+--error ER_QUERY_INTERRUPTED
+reap;
+
+--connection server_1
+SET gtid_domain_id=2;
+SET gtid_seq_no=2;
+INSERT INTO t1 VALUES (4);
+
+--connection s9
+reap;
+
+--connection server_2
+--replace_result $kill2_id KILL_ID
+eval KILL CONNECTION $kill2_id;
+
+--connection s6
+--error 2013
+reap;
+
+--connection server_1
+SET gtid_domain_id=1;
+SET gtid_seq_no=4;
+INSERT INTO t1 VALUES (5);
+SET gtid_domain_id=2;
+SET gtid_seq_no=5;
+INSERT INTO t1 VALUES (6);
+
+--connection s8
+reap;
+--connection s1
+reap;
+--connection s2
+reap;
+--connection s5
+reap;
+--connection s10
+reap;
+
+--connection server_1
+SET gtid_domain_id=2;
+SET gtid_seq_no=10;
+INSERT INTO t1 VALUES (7);
+
+--connection s4
+reap;
+--connection s7
+reap;
+
+
 --connection server_1
 DROP TABLE t1;

--- a/mysql-test/suite/rpl/t/rpl_gtid_crash.test
+++ b/mysql-test/suite/rpl/t/rpl_gtid_crash.test
@ -46,6 +46,7 @@ while ($1)
  dec $1;
 }
 --enable_query_log
+--source include/save_master_gtid.inc

 SET SESSION debug_dbug="+d,crash_dispatch_command_before";
 --error 2006,2013
@ -60,15 +61,14 @@ EOF
 --source include/wait_until_connected_again.inc

 --connection server_2
--let $wait_condition= SELECT COUNT(*) = 200 FROM t1 WHERE b=2
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 --connection server_1
 INSERT INTO t1 VALUES (1000, 3);
+--source include/save_master_gtid.inc

 --connection server_2
--let $wait_condition= SELECT COUNT(*) = 1 FROM t1 WHERE b=3
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 --connection server_1
 DROP TABLE t1;
@ -141,6 +141,7 @@ START SLAVE;

 --connection server_1
 INSERT INTO t1 VALUES (4);
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/wait_until_disconnected.inc
@ -152,8 +153,7 @@ EOF
 --enable_reconnect
 --source include/wait_until_connected_again.inc

--let $wait_condition= SELECT COUNT(*) = 4 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 # Crash the slave just before committing.
 --source include/stop_slave.inc
@ -165,6 +165,7 @@ START SLAVE;

 --connection server_1
 INSERT INTO t1 VALUES (5);
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/wait_until_disconnected.inc
@ -176,8 +177,7 @@ EOF
 --enable_reconnect
 --source include/wait_until_connected_again.inc

--let $wait_condition= SELECT COUNT(*) = 5 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 # Crash the slave just after committing.
 --source include/stop_slave.inc
@ -189,6 +189,7 @@ START SLAVE;

 --connection server_1
 INSERT INTO t1 VALUES (6);
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/wait_until_disconnected.inc
@ -200,8 +201,7 @@ EOF
 --enable_reconnect
 --source include/wait_until_connected_again.inc

--let $wait_condition= SELECT COUNT(*) = 6 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 # Crash the slave just before updating relay-log.info
 --source include/stop_slave.inc
@ -213,6 +213,7 @@ START SLAVE;

 --connection server_1
 INSERT INTO t1 VALUES (7);
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/wait_until_disconnected.inc
@ -224,8 +225,7 @@ EOF
 --enable_reconnect
 --source include/wait_until_connected_again.inc

--let $wait_condition= SELECT COUNT(*) = 7 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 # Crash the slave just after updating relay-log.info
 --source include/stop_slave.inc
@ -237,6 +237,7 @@ START SLAVE;

 --connection server_1
 INSERT INTO t1 VALUES (8);
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/wait_until_disconnected.inc
@ -248,8 +249,7 @@ EOF
 --enable_reconnect
 --source include/wait_until_connected_again.inc

--let $wait_condition= SELECT COUNT(*) = 8 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc


 # Check that everything was replicated correctly.
--- a/mysql-test/suite/rpl/t/rpl_gtid_errorhandling.test
+++ b/mysql-test/suite/rpl/t/rpl_gtid_errorhandling.test
@ -79,6 +79,7 @@ RESET MASTER;
 INSERT INTO t1 VALUES (2);
 # And this will be GTID 0-1-2
 INSERT INTO t1 VALUES (4);
+--source include/save_master_gtid.inc

 --connection slave
 SET sql_log_bin = 0;
@ -110,8 +111,7 @@ RESET MASTER;
 SET GLOBAL gtid_slave_pos = "0-1-1";

 START SLAVE;
--let $wait_condition= SELECT COUNT(*) = 4 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;

 --echo *** MDEV-4688: Empty value of @@GLOBAL.gtid_slave_pos ***
@ -125,6 +125,7 @@ SELECT * FROM t1 ORDER BY a;
 --connection master
 # This will be GTID 0-1-3
 INSERT INTO t1 VALUES (5);
+--source include/save_master_gtid.inc

 --connection slave
 SET @old_dbug= @@GLOBAL.debug_dbug;
@ -141,8 +142,7 @@ SELECT @@GLOBAL.gtid_slave_pos;
 SELECT * FROM t1 ORDER BY a;
 SET GLOBAL debug_dbug= @old_dbug;
 START SLAVE SQL_THREAD;
--let $wait_condition= SELECT COUNT(*) = 5 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;


@ -167,10 +167,10 @@ START SLAVE;

 --connection master
 INSERT INTO t1 VALUES (6);
+--source include/save_master_gtid.inc

 --connection slave
--let $wait_condition= SELECT COUNT(*) = 6 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;


--- a/mysql-test/suite/rpl/t/rpl_gtid_nobinlog.test
+++ b/mysql-test/suite/rpl/t/rpl_gtid_nobinlog.test
@ -32,12 +32,12 @@ START SLAVE;
 --connection server_2
 INSERT INTO t1 VALUES (3, 2);
 INSERT INTO t1 VALUES (4, 2);
+--source include/save_master_gtid.inc

 --source include/show_binlog_events.inc

 --connection server_1
--let $wait_condition= SELECT COUNT(*) = 4 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 SELECT * FROM t1 ORDER BY a;

@ -45,14 +45,14 @@ SELECT * FROM t1 ORDER BY a;
 RESET SLAVE;
 INSERT INTO t1 VALUES (5, 1);
 INSERT INTO t1 VALUES (6, 1);
+--source include/save_master_gtid.inc

 --connection server_2
 --replace_result $MASTER_MYPORT MASTER_PORT
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $MASTER_MYPORT,
     master_use_gtid = current_pos;
 START SLAVE;
--let $wait_condition= SELECT COUNT(*) = 6 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 SELECT * FROM t1 ORDER BY a;

--- a/mysql-test/suite/rpl/t/rpl_gtid_startpos.test
+++ b/mysql-test/suite/rpl/t/rpl_gtid_startpos.test
@ -67,6 +67,7 @@ SET sql_log_bin=1;

 --connection server_1
 INSERT INTO t1 VALUES(3);
+--source include/save_master_gtid.inc

 --connection server_2
 SET GLOBAL gtid_slave_pos='0-1-3';
@ -74,13 +75,13 @@ SET GLOBAL gtid_slave_pos='0-1-3';
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $MASTER_MYPORT,
     MASTER_USE_GTID=CURRENT_POS;
 --source include/start_slave.inc
--let $wait_condition= SELECT COUNT(*) = 3 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER by a;
 --source include/stop_slave.inc

 --connection server_1
 INSERT INTO t1 VALUES (4);
+--source include/save_master_gtid.inc

 --connection server_2
 # Now add some local transactions that conflict with the GTID position
@ -93,8 +94,7 @@ SET GLOBAL gtid_slave_pos='0-1-4';
 RESET MASTER;
 SET GLOBAL gtid_slave_pos='0-1-4';
 START SLAVE;
--let $wait_condition= SELECT COUNT(*) = 4 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER by a;

 --connection server_1
@ -200,10 +200,10 @@ CHANGE MASTER TO MASTER_USE_GTID=CURRENT_POS;

 --connection server_1
 INSERT INTO t1 VALUES(3);
+--source include/save_master_gtid.inc

 --connection server_2
--let $wait_condition= SELECT COUNT(*) = 3 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;
 SET SQL_LOG_BIN=0;
 call mtr.add_suppression("Slave: Table 't1' already exists error.* 1050");
@ -215,10 +215,10 @@ SET SQL_LOG_BIN=1;
 --connection server_1
 FLUSH LOGS;
 INSERT INTO t1 VALUES (4);
+--source include/save_master_gtid.inc

 --connection server_2
--let $wait_condition= SELECT COUNT(*) = 4 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 --source include/stop_slave.inc

 --connection server_1
@ -228,13 +228,13 @@ FLUSH LOGS;
 --source include/wait_for_purge.inc
 --source include/show_binary_logs.inc
 INSERT INTO t1 VALUES (5);
+--source include/save_master_gtid.inc

 --connection server_2
 --replace_result $MASTER_MYPORT MASTER_PORT
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $MASTER_MYPORT;
 --source include/start_slave.inc
--let $wait_condition= SELECT COUNT(*) = 5 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;


@ -249,11 +249,11 @@ SET GLOBAL gtid_slave_pos="";
 RESET MASTER;
 TRUNCATE TABLE t1;
 INSERT INTO t1 VALUES (10);   # Will be GTID 0-1-2
+--source include/save_master_gtid.inc

 --connection server_2
 --source include/start_slave.inc
--let $wait_condition= SELECT COUNT(*) = 1 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc

 SELECT * FROM t1;
 --let $value= query_get_value(SHOW SLAVE STATUS, "Using_Gtid", 1)
--- a/mysql-test/suite/rpl/t/rpl_gtid_stop_start.test
+++ b/mysql-test/suite/rpl/t/rpl_gtid_stop_start.test
@ -39,6 +39,7 @@ FLUSH LOGS;
 INSERT INTO t1 VALUES (2);
 FLUSH LOGS;
 INSERT INTO t1 VALUES (3);
+--source include/save_master_gtid.inc
 --source include/show_binary_logs.inc

 # Let the slave mysqld server start again.
@ -50,8 +51,7 @@ EOF
 --enable_reconnect
 --source include/wait_until_connected_again.inc

--let $wait_condition= SELECT COUNT(*) = 3 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;


@ -88,10 +88,10 @@ SHOW BINLOG EVENTS IN 'master-bin.000005' LIMIT 1,1;
 --source include/show_binary_logs.inc

 INSERT INTO t1 VALUES(5);
+--source include/save_master_gtid.inc

 --connection server_2
--let $wait_condition= SELECT COUNT(*) = 5 FROM t1
--source include/wait_condition.inc
+--source include/sync_with_master_gtid.inc
 SELECT * FROM t1 ORDER BY a;

 --echo *** Test that @@gtid_slave_pos and @@gtid_current_pos are correctly loaded even if slave threads have not started. ***
--- a/mysql-test/suite/sys_vars/r/last_gtid_basic.result
+++ b/mysql-test/suite/sys_vars/r/last_gtid_basic.result
@ -0,0 +1,9 @@
+SELECT @@global.last_gtid;
+ERROR HY000: Variable 'last_gtid' is a SESSION variable
+SET GLOBAL last_gtid= 10;
+ERROR HY000: Variable 'last_gtid' is a read only variable
+SET SESSION last_gtid= 20;
+ERROR HY000: Variable 'last_gtid' is a read only variable
+SELECT @@session.last_gtid;
+@@session.last_gtid
+
--- a/mysql-test/suite/sys_vars/t/last_gtid_basic.test
+++ b/mysql-test/suite/sys_vars/t/last_gtid_basic.test
@ -0,0 +1,11 @@
+--source include/not_embedded.inc
+
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@global.last_gtid;
+
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET GLOBAL last_gtid= 10;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET SESSION last_gtid= 20;
+
+SELECT @@session.last_gtid;
--- a/sql/item_create.cc
+++ b/sql/item_create.cc
@ -1783,6 +1783,19 @@ protected:
 };


+class Create_func_master_gtid_wait : public Create_native_func
+{
+public:
+  virtual Item *create_native(THD *thd, LEX_STRING name, List<Item> *item_list);
+
+  static Create_func_master_gtid_wait s_singleton;
+
+protected:
+  Create_func_master_gtid_wait() {}
+  virtual ~Create_func_master_gtid_wait() {}
+};
+
+
 class Create_func_md5 : public Create_func_arg1
 {
 public:
@ -4590,6 +4603,47 @@ Create_func_master_pos_wait::create_native(THD *thd, LEX_STRING name,
 }


+Create_func_master_gtid_wait Create_func_master_gtid_wait::s_singleton;
+
+Item*
+Create_func_master_gtid_wait::create_native(THD *thd, LEX_STRING name,
+                                            List<Item> *item_list)
+{
+  Item *func= NULL;
+  int arg_count= 0;
+
+  thd->lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_SYSTEM_FUNCTION);
+
+  if (item_list != NULL)
+    arg_count= item_list->elements;
+
+  if (arg_count < 1 || arg_count > 2)
+  {
+    my_error(ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT, MYF(0), name.str);
+    return func;
+  }
+
+  thd->lex->safe_to_cache_query= 0;
+
+  Item *param_1= item_list->pop();
+  switch (arg_count) {
+  case 1:
+  {
+    func= new (thd->mem_root) Item_master_gtid_wait(param_1);
+    break;
+  }
+  case 2:
+  {
+    Item *param_2= item_list->pop();
+    func= new (thd->mem_root) Item_master_gtid_wait(param_1, param_2);
+    break;
+  }
+  }
+
+  return func;
+}
+
+
 Create_func_md5 Create_func_md5::s_singleton;

 Item*
@ -5536,6 +5590,7 @@ static Native_func_registry func_array[] =
  { { C_STRING_WITH_LEN("MAKEDATE") }, BUILDER(Create_func_makedate)},
  { { C_STRING_WITH_LEN("MAKETIME") }, BUILDER(Create_func_maketime)},
  { { C_STRING_WITH_LEN("MAKE_SET") }, BUILDER(Create_func_make_set)},
+  { { C_STRING_WITH_LEN("MASTER_GTID_WAIT") }, BUILDER(Create_func_master_gtid_wait)},
  { { C_STRING_WITH_LEN("MASTER_POS_WAIT") }, BUILDER(Create_func_master_pos_wait)},
  { { C_STRING_WITH_LEN("MBRCONTAINS") }, GEOM_BUILDER(Create_func_mbr_contains)},
  { { C_STRING_WITH_LEN("MBRDISJOINT") }, GEOM_BUILDER(Create_func_mbr_disjoint)},
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@ -3991,6 +3991,34 @@ err:
 }


+longlong Item_master_gtid_wait::val_int()
+{
+  DBUG_ASSERT(fixed == 1);
+  longlong result= 0;
+
+  if (args[0]->null_value)
+  {
+    null_value= 1;
+    return 0;
+  }
+
+  null_value=0;
+#ifdef HAVE_REPLICATION
+  THD* thd= current_thd;
+  longlong timeout_us;
+  String *gtid_pos = args[0]->val_str(&value);
+
+  if (arg_count==2 && !args[1]->null_value)
+    timeout_us= (longlong)(1e6*args[1]->val_real());
+  else
+    timeout_us= (longlong)-1;
+
+  result= rpl_global_gtid_waiting.wait_for_pos(thd, gtid_pos, timeout_us);
+#endif
+  return result;
+}
+
+
 /**
  Enables a session to wait on a condition until a timeout or a network
  disconnect occurs.
--- a/sql/item_func.h
+++ b/sql/item_func.h
@ -1642,6 +1642,22 @@ public:
 };


+class Item_master_gtid_wait :public Item_int_func
+{
+  String value;
+public:
+  Item_master_gtid_wait(Item *a) :Item_int_func(a) {}
+  Item_master_gtid_wait(Item *a,Item *b) :Item_int_func(a,b) {}
+  longlong val_int();
+  const char *func_name() const { return "master_gtid_wait"; }
+  void fix_length_and_dec() { max_length=10+1+10+1+20+1; maybe_null=0;}
+  bool check_vcol_func_processor(uchar *int_arg) 
+  {
+    return trace_unsupported_by_check_vcol_func_processor(func_name());
+  }
+};
+
+
 /* Handling of user definable variables */

 class user_var_entry;
--- a/sql/log.cc
+++ b/sql/log.cc
@ -2933,7 +2933,7 @@ const char *MYSQL_LOG::generate_name(const char *log_name,


 MYSQL_BIN_LOG::MYSQL_BIN_LOG(uint *sync_period)
-  :reset_master_pending(false),
+  :reset_master_pending(false), mark_xid_done_waiting(0),
   bytes_written(0), file_id(1), open_count(1),
   group_commit_queue(0), group_commit_queue_busy(FALSE),
   num_commits(0), num_group_commits(0),
@ -3749,6 +3749,31 @@ bool MYSQL_BIN_LOG::reset_logs(THD* thd, bool create_new_log,
  const char* save_name;
  DBUG_ENTER("reset_logs");

+  if (!is_relay_log)
+  {
+    if (init_state && !is_empty_state())
+    {
+      my_error(ER_BINLOG_MUST_BE_EMPTY, MYF(0));
+      DBUG_RETURN(1);
+    }
+
+    /*
+      Mark that a RESET MASTER is in progress.
+      This ensures that a binlog checkpoint will not try to write binlog
+      checkpoint events, which would be useless (as we are deleting the binlog
+      anyway) and could deadlock, as we are holding LOCK_log.
+
+      Wait for any mark_xid_done() calls that might be already running to
+      complete (mark_xid_done_waiting counter to drop to zero); we need to
+      do this before we take the LOCK_log to not deadlock.
+    */
+    mysql_mutex_lock(&LOCK_xid_list);
+    reset_master_pending= true;
+    while (mark_xid_done_waiting > 0)
+      mysql_cond_wait(&COND_xid_list, &LOCK_xid_list);
+    mysql_mutex_unlock(&LOCK_xid_list);
+  }
+
  if (thd)
    ha_reset_logs(thd);
  /*
@ -3760,24 +3785,6 @@ bool MYSQL_BIN_LOG::reset_logs(THD* thd, bool create_new_log,

  if (!is_relay_log)
  {
-    if (init_state && !is_empty_state())
-    {
-      my_error(ER_BINLOG_MUST_BE_EMPTY, MYF(0));
-      mysql_mutex_unlock(&LOCK_index);
-      mysql_mutex_unlock(&LOCK_log);
-      DBUG_RETURN(1);
-    }
-
-    /*
-      Mark that a RESET MASTER is in progress.
-      This ensures that a binlog checkpoint will not try to write binlog
-      checkpoint events, which would be useless (as we are deleting the binlog
-      anyway) and could deadlock, as we are holding LOCK_log.
-    */
-    mysql_mutex_lock(&LOCK_xid_list);
-    reset_master_pending= true;
-    mysql_mutex_unlock(&LOCK_xid_list);
-
    /*
      We are going to nuke all binary log files.
      Without binlog, we cannot XA recover prepared-but-not-committed
@ -5446,6 +5453,7 @@ MYSQL_BIN_LOG::write_gtid_event(THD *thd, bool standalone,
  }
  if (err)
    return true;
+  thd->last_commit_gtid= gtid;

  Gtid_log_event gtid_event(thd, seq_no, domain_id, standalone,
                            LOG_EVENT_SUPPRESS_USE_F, is_transactional,
@ -8833,9 +8841,13 @@ TC_LOG_BINLOG::mark_xid_done(ulong binlog_id, bool write_checkpoint)
    locks in the opposite order.
  */

+  ++mark_xid_done_waiting;
  mysql_mutex_unlock(&LOCK_xid_list);
  mysql_mutex_lock(&LOCK_log);
  mysql_mutex_lock(&LOCK_xid_list);
+  --mark_xid_done_waiting;
+  if (unlikely(reset_master_pending))
+    mysql_cond_signal(&COND_xid_list);
  /* We need to reload current_binlog_id due to release/re-take of lock. */
  current= current_binlog_id;

--- a/sql/log.h
+++ b/sql/log.h
@ -471,6 +471,7 @@ class MYSQL_BIN_LOG: public TC_LOG, private MYSQL_LOG
    checkpoint arrives - when all have arrived, RESET MASTER will complete.
  */
  bool reset_master_pending;
+  ulong mark_xid_done_waiting;

  /* LOCK_log and LOCK_index are inited by init_pthread_objects() */
  mysql_mutex_t LOCK_index;
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@ -780,6 +780,7 @@ PSI_mutex_key key_LOCK_stats,
  key_LOCK_global_user_client_stats, key_LOCK_global_table_stats,
  key_LOCK_global_index_stats,
  key_LOCK_wakeup_ready, key_LOCK_wait_commit;
+PSI_mutex_key key_LOCK_gtid_waiting;

 PSI_mutex_key key_LOCK_prepare_ordered, key_LOCK_commit_ordered;

@ -825,6 +826,7 @@ static PSI_mutex_info all_server_mutexes[]=
  { &key_LOCK_global_index_stats, "LOCK_global_index_stats", PSI_FLAG_GLOBAL},
  { &key_LOCK_wakeup_ready, "THD::LOCK_wakeup_ready", 0},
  { &key_LOCK_wait_commit, "wait_for_commit::LOCK_wait_commit", 0},
+  { &key_LOCK_gtid_waiting, "gtid_waiting::LOCK_gtid_waiting", 0},
  { &key_LOCK_thd_data, "THD::LOCK_thd_data", 0},
  { &key_LOCK_user_conn, "LOCK_user_conn", PSI_FLAG_GLOBAL},
  { &key_LOCK_uuid_short_generator, "LOCK_uuid_short_generator", PSI_FLAG_GLOBAL},
@ -895,6 +897,7 @@ PSI_cond_key key_RELAYLOG_COND_queue_busy;
 PSI_cond_key key_TC_LOG_MMAP_COND_queue_busy;
 PSI_cond_key key_COND_rpl_thread, key_COND_rpl_thread_pool,
  key_COND_parallel_entry, key_COND_prepare_ordered;
+PSI_cond_key key_COND_wait_gtid;

 static PSI_cond_info all_server_conds[]=
 {
@ -940,7 +943,8 @@ static PSI_cond_info all_server_conds[]=
  { &key_COND_rpl_thread, "COND_rpl_thread", 0},
  { &key_COND_rpl_thread_pool, "COND_rpl_thread_pool", 0},
  { &key_COND_parallel_entry, "COND_parallel_entry", 0},
-  { &key_COND_prepare_ordered, "COND_prepare_ordered", 0}
+  { &key_COND_prepare_ordered, "COND_prepare_ordered", 0},
+  { &key_COND_wait_gtid, "COND_wait_gtid", 0}
 };

 PSI_thread_key key_thread_bootstrap, key_thread_delayed_insert,
@ -1821,6 +1825,7 @@ static void mysqld_exit(int exit_code)
    but if a kill -15 signal was sent, the signal thread did
    spawn the kill_server_thread thread, which is running concurrently.
  */
+  rpl_deinit_gtid_waiting();
  rpl_deinit_gtid_slave_state();
  wait_for_signal_thread_to_end();
  mysql_audit_finalize();
@ -4202,6 +4207,7 @@ static int init_thread_environment()

 #ifdef HAVE_REPLICATION
  rpl_init_gtid_slave_state();
+  rpl_init_gtid_waiting();
 #endif

  DBUG_RETURN(0);
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@ -256,6 +256,7 @@ extern PSI_mutex_key key_LOCK_slave_state, key_LOCK_binlog_state,
 extern PSI_mutex_key key_LOCK_stats,
  key_LOCK_global_user_client_stats, key_LOCK_global_table_stats,
  key_LOCK_global_index_stats, key_LOCK_wakeup_ready, key_LOCK_wait_commit;
+extern PSI_mutex_key key_LOCK_gtid_waiting;

 extern PSI_rwlock_key key_rwlock_LOCK_grant, key_rwlock_LOCK_logger,
  key_rwlock_LOCK_sys_init_connect, key_rwlock_LOCK_sys_init_slave,
@ -285,6 +286,7 @@ extern PSI_cond_key key_RELAYLOG_COND_queue_busy;
 extern PSI_cond_key key_TC_LOG_MMAP_COND_queue_busy;
 extern PSI_cond_key key_COND_rpl_thread, key_COND_rpl_thread_pool,
  key_COND_parallel_entry;
+extern PSI_cond_key key_COND_wait_gtid;

 extern PSI_thread_key key_thread_bootstrap, key_thread_delayed_insert,
  key_thread_handle_manager, key_thread_kill_server, key_thread_main,
--- a/sql/rpl_gtid.cc
+++ b/sql/rpl_gtid.cc
@ -43,9 +43,9 @@ rpl_slave_state::update_state_hash(uint64 sub_id, rpl_gtid *gtid)
    there will not be an attempt to delete the corresponding table row before
    it is even committed.
  */
-  lock();
+  mysql_mutex_lock(&LOCK_slave_state);
  err= update(gtid->domain_id, gtid->server_id, sub_id, gtid->seq_no);
-  unlock();
+  mysql_mutex_unlock(&LOCK_slave_state);
  if (err)
  {
    sql_print_warning("Slave: Out of memory during slave state maintenance. "
@ -82,11 +82,20 @@ rpl_slave_state::record_and_update_gtid(THD *thd, rpl_group_info *rgi)
 }


+static void
+rpl_slave_state_free_element(void *arg)
+{
+  struct rpl_slave_state::element *elem= (struct rpl_slave_state::element *)arg;
+  mysql_cond_destroy(&elem->COND_wait_gtid);
+  my_free(elem);
+}
+
+
 rpl_slave_state::rpl_slave_state()
  : last_sub_id(0), inited(false), loaded(false)
 {
  my_hash_init(&hash, &my_charset_bin, 32, offsetof(element, domain_id),
-               sizeof(uint32), NULL, my_free, HASH_UNIQUE);
+               sizeof(uint32), NULL, rpl_slave_state_free_element, HASH_UNIQUE);
 }


@ -146,6 +155,21 @@ rpl_slave_state::update(uint32 domain_id, uint32 server_id, uint64 sub_id,
  if (!(elem= get_element(domain_id)))
    return 1;

+  if (seq_no > elem->highest_seq_no)
+    elem->highest_seq_no= seq_no;
+  if (elem->gtid_waiter && elem->min_wait_seq_no <= seq_no)
+  {
+    /*
+      Someone was waiting in MASTER_GTID_WAIT() for this GTID to appear.
+      Signal (and remove) them. The waiter will handle all the processing
+      of all pending MASTER_GTID_WAIT(), so we do not slow down the
+      replication SQL thread.
+    */
+    mysql_mutex_assert_owner(&LOCK_slave_state);
+    elem->gtid_waiter= NULL;
+    mysql_cond_broadcast(&elem->COND_wait_gtid);
+  }
+
  if (!(list_elem= (list_element *)my_malloc(sizeof(*list_elem), MYF(MY_WME))))
    return 1;
  list_elem->server_id= server_id;
@ -173,6 +197,9 @@ rpl_slave_state::get_element(uint32 domain_id)
    return NULL;
  elem->list= NULL;
  elem->domain_id= domain_id;
+  elem->highest_seq_no= 0;
+  elem->gtid_waiter= NULL;
+  mysql_cond_init(key_COND_wait_gtid, &elem->COND_wait_gtid, 0);
  if (my_hash_insert(&hash, (uchar *)elem))
  {
    my_free(elem);
@ -378,10 +405,10 @@ rpl_slave_state::record_gtid(THD *thd, const rpl_gtid *gtid, uint64 sub_id,
    goto end;
  }

-  lock();
+  mysql_mutex_lock(&LOCK_slave_state);
  if ((elem= get_element(gtid->domain_id)) == NULL)
  {
-    unlock();
+    mysql_mutex_unlock(&LOCK_slave_state);
    my_error(ER_OUT_OF_RESOURCES, MYF(0));
    err= 1;
    goto end;
@ -410,7 +437,7 @@ rpl_slave_state::record_gtid(THD *thd, const rpl_gtid *gtid, uint64 sub_id,
    cur->next= NULL;
    elem->list= cur;
  }
-  unlock();
+  mysql_mutex_unlock(&LOCK_slave_state);

  if (!elist)
    goto end;
@ -470,9 +497,9 @@ end:
      */
      if (elist)
      {
-        lock();
+        mysql_mutex_lock(&LOCK_slave_state);
        put_back_list(gtid->domain_id, elist);
-        unlock();
+        mysql_mutex_unlock(&LOCK_slave_state);
      }

      ha_rollback_trans(thd, FALSE);
@ -499,9 +526,9 @@ rpl_slave_state::next_sub_id(uint32 domain_id)
 {
  uint64 sub_id= 0;

-  lock();
+  mysql_mutex_lock(&LOCK_slave_state);
  sub_id= ++last_sub_id;
-  unlock();
+  mysql_mutex_unlock(&LOCK_slave_state);

  return sub_id;
 }
@ -541,7 +568,7 @@ rpl_slave_state::iterate(int (*cb)(rpl_gtid *, void *), void *data,
        my_hash_insert(&gtid_hash, (uchar *)(&extra_gtids[i])))
      goto err;

-  lock();
+  mysql_mutex_lock(&LOCK_slave_state);

  for (i= 0; i < hash.records; ++i)
  {
@ -576,19 +603,19 @@ rpl_slave_state::iterate(int (*cb)(rpl_gtid *, void *), void *data,
        memcpy(&best_gtid, gtid, sizeof(best_gtid));
      if (my_hash_delete(&gtid_hash, rec))
      {
-        unlock();
+        mysql_mutex_unlock(&LOCK_slave_state);
        goto err;
      }
    }

    if ((res= (*cb)(&best_gtid, data)))
    {
-      unlock();
+      mysql_mutex_unlock(&LOCK_slave_state);
      goto err;
    }
  }

-  unlock();
+  mysql_mutex_unlock(&LOCK_slave_state);

  /* Also add any remaining extra domain_ids. */
  for (i= 0; i < gtid_hash.records; ++i)
@ -659,11 +686,11 @@ rpl_slave_state::domain_to_gtid(uint32 domain_id, rpl_gtid *out_gtid)
  list_element *list;
  uint64 best_sub_id;

-  lock();
+  mysql_mutex_lock(&LOCK_slave_state);
  elem= (element *)my_hash_search(&hash, (const uchar *)&domain_id, 0);
  if (!elem || !(list= elem->list))
  {
-    unlock();
+    mysql_mutex_unlock(&LOCK_slave_state);
    return false;
  }

@ -681,7 +708,7 @@ rpl_slave_state::domain_to_gtid(uint32 domain_id, rpl_gtid *out_gtid)
    out_gtid->seq_no= list->seq_no;
  }

-  unlock();
+  mysql_mutex_unlock(&LOCK_slave_state);
  return true;
 }

@ -811,7 +838,7 @@ rpl_slave_state::is_empty()
  uint32 i;
  bool result= true;

-  lock();
+  mysql_mutex_lock(&LOCK_slave_state);
  for (i= 0; i < hash.records; ++i)
  {
    element *e= (element *)my_hash_element(&hash, i);
@ -821,7 +848,7 @@ rpl_slave_state::is_empty()
      break;
    }
  }
-  unlock();
+  mysql_mutex_unlock(&LOCK_slave_state);

  return result;
 }
@ -1647,3 +1674,445 @@ slave_connection_state::get_gtid_list(rpl_gtid *gtid_list, uint32 list_size)

  return 0;
 }
+
+
+/*
+  Execute a MASTER_GTID_WAIT().
+  The position to wait for is in gtid_str in string form.
+  The timeout in microseconds is in timeout_us, zero means no timeout.
+
+  Returns:
+   1 for error.
+   0 for wait completed.
+  -1 for wait timed out.
+*/
+int
+gtid_waiting::wait_for_pos(THD *thd, String *gtid_str, longlong timeout_us)
+{
+  int err;
+  rpl_gtid *wait_pos;
+  uint32 count, i;
+  struct timespec wait_until, *wait_until_ptr;
+
+  /* Wait for the empty position returns immediately. */
+  if (gtid_str->length() == 0)
+    return 0;
+
+  if (!(wait_pos= gtid_parse_string_to_list(gtid_str->ptr(), gtid_str->length(),
+                                            &count)))
+  {
+    my_error(ER_INCORRECT_GTID_STATE, MYF(0));
+    return 1;
+  }
+
+  if (timeout_us >= 0)
+  {
+    set_timespec_nsec(wait_until, (ulonglong)1000*timeout_us);
+    wait_until_ptr= &wait_until;
+  }
+  else
+    wait_until_ptr= NULL;
+  err= 0;
+  for (i= 0; i < count; ++i)
+  {
+    if ((err= wait_for_gtid(thd, &wait_pos[i], wait_until_ptr)))
+      break;
+  }
+  my_free(wait_pos);
+  return err;
+}
+
+
+void
+gtid_waiting::promote_new_waiter(gtid_waiting::hash_element *he)
+{
+  queue_element *qe;
+
+  mysql_mutex_assert_owner(&LOCK_gtid_waiting);
+  if (queue_empty(&he->queue))
+    return;
+  qe= (queue_element *)queue_top(&he->queue);
+  qe->do_small_wait= true;
+  mysql_cond_signal(&qe->thd->COND_wakeup_ready);
+}
+
+void
+gtid_waiting::process_wait_hash(uint64 wakeup_seq_no,
+                                gtid_waiting::hash_element *he)
+{
+  mysql_mutex_assert_owner(&LOCK_gtid_waiting);
+
+  for (;;)
+  {
+    queue_element *qe;
+
+    if (queue_empty(&he->queue))
+      break;
+    qe= (queue_element *)queue_top(&he->queue);
+    if (qe->wait_seq_no > wakeup_seq_no)
+      break;
+    DBUG_ASSERT(!qe->done);
+    queue_remove_top(&he->queue);
+    qe->done= true;;
+    mysql_cond_signal(&qe->thd->COND_wakeup_ready);
+  }
+}
+
+
+/*
+  Execute a MASTER_GTID_WAIT() for one specific domain.
+
+  The implementation is optimised primarily for (1) minimal performance impact
+  on the slave replication threads, and secondarily for (2) quick performance
+  of MASTER_GTID_WAIT() on a single GTID, which can be useful for consistent
+  read to clients in an async replication read-scaleout scenario.
+
+  To achieve (1), we have a "small" wait and a "large" wait. The small wait
+  contends with the replication threads on the lock on the gtid_slave_pos, so
+  only minimal processing is done under that lock, and only a single waiter at
+  a time does the small wait.
+
+  If there is already a small waiter, a new thread will either replace the
+  small waiter (if it needs to wait for an earlier sequence number), or
+  instead do a "large" wait.
+
+  Once awoken on the small wait, the waiting thread releases the lock shared
+  with the SQL threads quickly, and then processes all waiters currently doing
+  the large wait using a different lock that does not impact replication.
+
+  This way, the SQL threads only need to do a single check + possibly a
+  pthread_cond_signal() when updating the gtid_slave_state, and the time that
+  non-SQL threads contend for the lock on gtid_slave_state is minimized.
+
+  There is always at least one thread that has the responsibility to ensure
+  that there is a small waiter; this thread has queue_element::do_small_wait
+  set to true. This thread will do the small wait until it is done, at which
+  point it will make sure to pass on the responsibility to another thread.
+  Normally only one thread has do_small_wait==true, but it can occasionally
+  happen that there is more than one, when threads race one another for the
+  lock on the small wait (this results in slightly increased activity on the
+  small lock but is otherwise harmless).
+
+  Returns:
+     0  Wait completed normally
+    -1  Wait completed due to timeout
+     1  An error (my_error() will have been called to set the error in the da)
+*/
+int
+gtid_waiting::wait_for_gtid(THD *thd, rpl_gtid *wait_gtid,
+                            struct timespec *wait_until)
+{
+  bool timed_out= false;
+#ifdef HAVE_REPLICATION
+  queue_element elem;
+  uint32 domain_id= wait_gtid->domain_id;
+  uint64 seq_no= wait_gtid->seq_no;
+  hash_element *he;
+  rpl_slave_state::element *slave_state_elem= NULL;
+  const char *old_msg= NULL;
+  bool did_enter_cond= false;
+
+  elem.wait_seq_no= seq_no;
+  elem.thd= thd;
+  elem.done= false;
+
+  mysql_mutex_lock(&LOCK_gtid_waiting);
+  if (!(he= get_entry(wait_gtid->domain_id)))
+  {
+    mysql_mutex_unlock(&LOCK_gtid_waiting);
+    return 1;
+  }
+  /*
+    If there is already another waiter with seq_no no larger than our own,
+    we are sure that there is already a small waiter that will wake us up
+    (or later pass the small wait responsibility to us). So in this case, we
+    do not need to touch the small wait lock at all.
+  */
+  elem.do_small_wait=
+    (queue_empty(&he->queue) ||
+     ((queue_element *)queue_top(&he->queue))->wait_seq_no > seq_no);
+
+  if (register_in_wait_queue(thd, wait_gtid, he, &elem))
+  {
+    mysql_mutex_unlock(&LOCK_gtid_waiting);
+    return 1;
+  }
+  /*
+    Loop, doing either the small or large wait as appropriate, until either
+    the position waited for is reached, or we get a kill or timeout.
+  */
+  for (;;)
+  {
+    mysql_mutex_assert_owner(&LOCK_gtid_waiting);
+
+    if (elem.do_small_wait)
+    {
+      uint64 wakeup_seq_no;
+      queue_element *cur_waiter;
+
+      mysql_mutex_lock(&rpl_global_gtid_slave_state.LOCK_slave_state);
+      /*
+        The elements in the gtid_slave_state_hash are never re-allocated once
+        they enter the hash, so we do not need to re-do the lookup after releasing
+        and re-aquiring the lock.
+      */
+      if (!slave_state_elem &&
+          !(slave_state_elem= rpl_global_gtid_slave_state.get_element(domain_id)))
+      {
+        mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
+        remove_from_wait_queue(he, &elem);
+        promote_new_waiter(he);
+        if (did_enter_cond)
+          thd->exit_cond(old_msg);
+        else
+          mysql_mutex_unlock(&LOCK_gtid_waiting);
+        my_error(ER_OUT_OF_RESOURCES, MYF(0));
+        return 1;
+      }
+
+      if ((wakeup_seq_no= slave_state_elem->highest_seq_no) >= seq_no)
+      {
+        /*
+          We do not have to wait. (We will be removed from the wait queue when
+          we call process_wait_hash() below.
+        */
+        mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
+      }
+      else if ((cur_waiter= slave_state_elem->gtid_waiter) &&
+               slave_state_elem->min_wait_seq_no <= seq_no)
+      {
+        /*
+          There is already a suitable small waiter, go do the large wait.
+          (Normally we would not have needed to check the small wait in this
+          case, but it can happen if we race with another thread for the small
+          lock).
+        */
+        elem.do_small_wait= false;
+        mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
+      }
+      else
+      {
+        /*
+          We have to do the small wait ourselves (stealing it from any thread
+          that might already be waiting for a later seq_no).
+        */
+        slave_state_elem->gtid_waiter= &elem;
+        slave_state_elem->min_wait_seq_no= seq_no;
+        if (cur_waiter)
+        {
+          /* We stole the wait, so wake up the old waiting thread. */
+          mysql_cond_signal(&slave_state_elem->COND_wait_gtid);
+        }
+
+        /* Release the large lock, and do the small wait. */
+        if (did_enter_cond)
+        {
+          thd->exit_cond(old_msg);
+          did_enter_cond= false;
+        }
+        else
+          mysql_mutex_unlock(&LOCK_gtid_waiting);
+        old_msg=
+          thd->enter_cond(&slave_state_elem->COND_wait_gtid,
+                          &rpl_global_gtid_slave_state.LOCK_slave_state,
+                          "Waiting in MASTER_GTID_WAIT() (primary waiter)");
+        do
+        {
+          if (thd->check_killed())
+            break;
+          else if (wait_until)
+          {
+            int err=
+              mysql_cond_timedwait(&slave_state_elem->COND_wait_gtid,
+                                   &rpl_global_gtid_slave_state.LOCK_slave_state,
+                                   wait_until);
+            if (err == ETIMEDOUT || err == ETIME)
+            {
+              timed_out= true;
+              break;
+            }
+          }
+          else
+            mysql_cond_wait(&slave_state_elem->COND_wait_gtid,
+                            &rpl_global_gtid_slave_state.LOCK_slave_state);
+        } while (slave_state_elem->gtid_waiter == &elem);
+        wakeup_seq_no= slave_state_elem->highest_seq_no;
+        /*
+          If we aborted due to timeout or kill, remove us as waiter.
+
+          If we were replaced by another waiter with a smaller seq_no, then we
+          no longer have responsibility for the small wait.
+        */
+        if ((cur_waiter= slave_state_elem->gtid_waiter))
+        {
+          if (cur_waiter == &elem)
+            slave_state_elem->gtid_waiter= NULL;
+          else if (slave_state_elem->min_wait_seq_no <= seq_no)
+            elem.do_small_wait= false;
+        }
+        thd->exit_cond(old_msg);
+
+        mysql_mutex_lock(&LOCK_gtid_waiting);
+      }
+
+      /*
+        Note that hash_entry pointers do not change once allocated, so we do
+        not need to lookup `he' again after re-aquiring LOCK_gtid_waiting.
+      */
+      process_wait_hash(wakeup_seq_no, he);
+    }
+    else
+    {
+      /* Do the large wait. */
+      if (!did_enter_cond)
+      {
+        old_msg= thd->enter_cond(&thd->COND_wakeup_ready, &LOCK_gtid_waiting,
+                                 "Waiting in MASTER_GTID_WAIT()");
+        did_enter_cond= true;
+      }
+      while (!elem.done && !thd->check_killed())
+      {
+        thd_wait_begin(thd, THD_WAIT_BINLOG);
+        if (wait_until)
+        {
+          int err= mysql_cond_timedwait(&thd->COND_wakeup_ready,
+                                        &LOCK_gtid_waiting, wait_until);
+          if (err == ETIMEDOUT || err == ETIME)
+            timed_out= true;
+        }
+        else
+          mysql_cond_wait(&thd->COND_wakeup_ready, &LOCK_gtid_waiting);
+        thd_wait_end(thd);
+        if (elem.do_small_wait || timed_out)
+          break;
+      }
+    }
+
+    if ((thd->killed || timed_out) && !elem.done)
+    {
+      /* Aborted, so remove ourselves from the hash. */
+      remove_from_wait_queue(he, &elem);
+      elem.done= true;
+    }
+    if (elem.done)
+    {
+      /*
+        If our wait is done, but we have (or were passed) responsibility for
+        the small wait, then we need to pass on that task to someone else.
+      */
+      if (elem.do_small_wait)
+        promote_new_waiter(he);
+      break;
+    }
+  }
+
+  if (did_enter_cond)
+    thd->exit_cond(old_msg);
+  else
+    mysql_mutex_unlock(&LOCK_gtid_waiting);
+  if (thd->killed)
+    thd->send_kill_message();
+#endif  /* HAVE_REPLICATION */
+  return timed_out ? -1 : 0;
+}
+
+
+static void
+free_hash_element(void *p)
+{
+  gtid_waiting::hash_element *e= (gtid_waiting::hash_element *)p;
+  delete_queue(&e->queue);
+  my_free(e);
+}
+
+
+void
+gtid_waiting::init()
+{
+  my_hash_init(&hash, &my_charset_bin, 32,
+               offsetof(hash_element, domain_id), sizeof(uint32), NULL,
+               free_hash_element, HASH_UNIQUE);
+  mysql_mutex_init(key_LOCK_gtid_waiting, &LOCK_gtid_waiting, 0);
+}
+
+
+void
+gtid_waiting::destroy()
+{
+  mysql_mutex_destroy(&LOCK_gtid_waiting);
+  my_hash_free(&hash);
+}
+
+
+static int
+cmp_queue_elem(void *, uchar *a, uchar *b)
+{
+  uint64 seq_no_a= *(uint64 *)a;
+  uint64 seq_no_b= *(uint64 *)b;
+  if (seq_no_a < seq_no_b)
+    return -1;
+  else if (seq_no_a == seq_no_b)
+    return 0;
+  else
+    return 1;
+}
+
+
+gtid_waiting::hash_element *
+gtid_waiting::get_entry(uint32 domain_id)
+{
+  hash_element *e;
+
+  if ((e= (hash_element *)my_hash_search(&hash, (const uchar *)&domain_id, 0)))
+    return e;
+
+  if (!(e= (hash_element *)my_malloc(sizeof(*e), MYF(MY_WME))))
+  {
+    my_error(ER_OUTOFMEMORY, MYF(0), sizeof(*e));
+    return NULL;
+  }
+
+  if (init_queue(&e->queue, 8, offsetof(queue_element, wait_seq_no), 0,
+                 cmp_queue_elem, NULL, 1+offsetof(queue_element, queue_idx), 1))
+  {
+    my_error(ER_OUT_OF_RESOURCES, MYF(0));
+    my_free(e);
+    return NULL;
+  }
+  e->domain_id= domain_id;
+  if (my_hash_insert(&hash, (uchar *)e))
+  {
+    my_error(ER_OUT_OF_RESOURCES, MYF(0));
+    delete_queue(&e->queue);
+    my_free(e);
+    return NULL;
+  }
+  return e;
+}
+
+
+int
+gtid_waiting::register_in_wait_queue(THD *thd, rpl_gtid *wait_gtid,
+                                     gtid_waiting::hash_element *he,
+                                     gtid_waiting::queue_element *elem)
+{
+  mysql_mutex_assert_owner(&LOCK_gtid_waiting);
+
+  if (queue_insert_safe(&he->queue, (uchar *)elem))
+  {
+    my_error(ER_OUT_OF_RESOURCES, MYF(0));
+    return 1;
+  }
+
+  return 0;
+}
+
+
+void
+gtid_waiting::remove_from_wait_queue(gtid_waiting::hash_element *he,
+                                     gtid_waiting::queue_element *elem)
+{
+  mysql_mutex_assert_owner(&LOCK_gtid_waiting);
+
+  queue_remove(&he->queue, elem->queue_idx);
+}
--- a/sql/rpl_gtid.h
+++ b/sql/rpl_gtid.h
@ -16,6 +16,10 @@
 #ifndef RPL_GTID_H
 #define RPL_GTID_H

+#include "hash.h"
+#include "queues.h"
+
+
 /* Definitions for MariaDB global transaction ID (GTID). */


@ -36,6 +40,57 @@ enum enum_gtid_skip_type {
 };


+/*
+  Structure to keep track of threads waiting in MASTER_GTID_WAIT().
+
+  Since replication is (mostly) single-threaded, we want to minimise the
+  performance impact on that from MASTER_GTID_WAIT(). To achieve this, we
+  are careful to keep the common lock between replication threads and
+  MASTER_GTID_WAIT threads held for as short as possible. We keep only
+  a single thread waiting to be notified by the replication threads; this
+  thread then handles all the (potentially heavy) lifting of dealing with
+  all current waiting threads.
+*/
+struct gtid_waiting {
+  /* Elements in the hash, basically a priority queue for each domain. */
+  struct hash_element {
+    QUEUE queue;
+    uint32 domain_id;
+  };
+  /* A priority queue to handle waiters in one domain in seq_no order. */
+  struct queue_element {
+    uint64 wait_seq_no;
+    THD *thd;
+    int queue_idx;
+    /*
+      do_small_wait is true if we have responsibility for ensuring that there
+      is a small waiter.
+    */
+    bool do_small_wait;
+    /*
+      The flag `done' is set when the wait is completed (either due to reaching
+      the position waited for, or due to timeout or kill). The queue_element
+      is in the queue if and only if `done' is true.
+    */
+    bool done;
+  };
+
+  mysql_mutex_t LOCK_gtid_waiting;
+  HASH hash;
+
+  void init();
+  void destroy();
+  hash_element *get_entry(uint32 domain_id);
+  int wait_for_pos(THD *thd, String *gtid_str, longlong timeout_us);
+  void promote_new_waiter(gtid_waiting::hash_element *he);
+  int wait_for_gtid(THD *thd, rpl_gtid *wait_gtid, struct timespec *wait_until);
+  void process_wait_hash(uint64 wakeup_seq_no, gtid_waiting::hash_element *he);
+  int register_in_wait_queue(THD *thd, rpl_gtid *wait_gtid, hash_element *he,
+                             queue_element *elem);
+  void remove_from_wait_queue(hash_element *he, queue_element *elem);
+};
+
+
 /*
  Replication slave state.

@ -61,6 +116,20 @@ struct rpl_slave_state
  {
    struct list_element *list;
    uint32 domain_id;
+    /* Highest seq_no seen so far in this domain. */
+    uint64 highest_seq_no;
+    /*
+      If this is non-NULL, then it is the waiter responsible for the small
+      wait in MASTER_GTID_WAIT().
+    */
+    gtid_waiting::queue_element *gtid_waiter;
+    /*
+      If gtid_waiter is non-NULL, then this is the seq_no that its
+      MASTER_GTID_WAIT() is waiting on. When we reach this seq_no, we need to
+      signal the waiter on COND_wait_gtid.
+    */
+    uint64 min_wait_seq_no;
+    mysql_cond_t COND_wait_gtid;

    list_element *grab_list() { list_element *l= list; list= NULL; return l; }
    void add(list_element *l)
@ -99,9 +168,6 @@ struct rpl_slave_state
           bool in_statement);
  bool is_empty();

-  void lock() { DBUG_ASSERT(inited); mysql_mutex_lock(&LOCK_slave_state); }
-  void unlock() { DBUG_ASSERT(inited); mysql_mutex_unlock(&LOCK_slave_state); }
-
  element *get_element(uint32 domain_id);
  int put_back_list(uint32 domain_id, list_element *list);

@ -204,6 +270,7 @@ struct slave_connection_state
  int get_gtid_list(rpl_gtid *gtid_list, uint32 list_size);
 };

+
 extern bool rpl_slave_state_tostring_helper(String *dest, const rpl_gtid *gtid,
                                            bool *first);
 extern int gtid_check_rpl_slave_state_table(TABLE *table);
--- a/sql/rpl_rli.cc
+++ b/sql/rpl_rli.cc
@ -37,6 +37,8 @@ static int count_relay_log_space(Relay_log_info* rli);
   domain).
 */
 rpl_slave_state rpl_global_gtid_slave_state;
+/* Object used for MASTER_GTID_WAIT(). */
+gtid_waiting rpl_global_gtid_waiting;


 // Defined in slave.cc
@ -1317,9 +1319,9 @@ rpl_load_gtid_slave_state(THD *thd)
  uint32 i;
  DBUG_ENTER("rpl_load_gtid_slave_state");

-  rpl_global_gtid_slave_state.lock();
+  mysql_mutex_lock(&rpl_global_gtid_slave_state.LOCK_slave_state);
  bool loaded= rpl_global_gtid_slave_state.loaded;
-  rpl_global_gtid_slave_state.unlock();
+  mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
  if (loaded)
    DBUG_RETURN(0);

@ -1419,10 +1421,10 @@ rpl_load_gtid_slave_state(THD *thd)
    }
  }

-  rpl_global_gtid_slave_state.lock();
+  mysql_mutex_lock(&rpl_global_gtid_slave_state.LOCK_slave_state);
  if (rpl_global_gtid_slave_state.loaded)
  {
-    rpl_global_gtid_slave_state.unlock();
+    mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
    goto end;
  }

@ -1434,7 +1436,7 @@ rpl_load_gtid_slave_state(THD *thd)
                                                 tmp_entry.sub_id,
                                                 tmp_entry.gtid.seq_no)))
    {
-      rpl_global_gtid_slave_state.unlock();
+      mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
      my_error(ER_OUT_OF_RESOURCES, MYF(0));
      goto end;
    }
@ -1447,14 +1449,14 @@ rpl_load_gtid_slave_state(THD *thd)
        mysql_bin_log.bump_seq_no_counter_if_needed(entry->gtid.domain_id,
                                                    entry->gtid.seq_no))
    {
-      rpl_global_gtid_slave_state.unlock();
+      mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);
      my_error(ER_OUT_OF_RESOURCES, MYF(0));
      goto end;
    }
  }

  rpl_global_gtid_slave_state.loaded= true;
-  rpl_global_gtid_slave_state.unlock();
+  mysql_mutex_unlock(&rpl_global_gtid_slave_state.LOCK_slave_state);

  err= 0;                                       /* Clear HA_ERR_END_OF_FILE */

--- a/sql/rpl_rli.h
+++ b/sql/rpl_rli.h
@ -708,6 +708,7 @@ int init_relay_log_info(Relay_log_info* rli, const char* info_fname);


 extern struct rpl_slave_state rpl_global_gtid_slave_state;
+extern gtid_waiting rpl_global_gtid_waiting;

 int rpl_load_gtid_slave_state(THD *thd);
 int event_group_new_gtid(rpl_group_info *rgi, Gtid_log_event *gev);
--- a/sql/share/errmsg-utf8.txt
+++ b/sql/share/errmsg-utf8.txt
@ -6524,7 +6524,7 @@ ER_UNTIL_REQUIRES_USING_GTID
 ER_GTID_STRICT_OUT_OF_ORDER
 	eng "An attempt was made to binlog GTID %u-%u-%llu which would create an out-of-order sequence number with existing GTID %u-%u-%llu, and gtid strict mode is enabled."
 ER_GTID_START_FROM_BINLOG_HOLE
-	eng "The binlog on the master is missing the GTID %u-%u-%llu requested by the slave (even though both a prior and a subsequent sequence number does exist), and GTID strict mode is enabled"
+	eng "The binlog on the master is missing the GTID %u-%u-%llu requested by the slave (even though a subsequent sequence number does exist), and GTID strict mode is enabled"
 ER_SLAVE_UNEXPECTED_MASTER_SWITCH
 	eng "Unexpected GTID received from master after reconnect. This normally indicates that the master server was replaced without restarting the slave threads. %s"
 ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_GTID_DOMAIN_ID_SEQ_NO
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@ -1267,6 +1267,7 @@ void THD::init(void)
  set_status_var_init();
  bzero((char *) &org_status_var, sizeof(org_status_var));
  start_bytes_received= 0;
+  last_commit_gtid.seq_no= 0;

  if (variables.sql_log_bin)
    variables.option_bits|= OPTION_BIN_LOG;
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@ -44,6 +44,7 @@
 #include "thr_lock.h"             /* thr_lock_type, THR_LOCK_DATA,
                                     THR_LOCK_INFO */
 #include "my_apc.h"
+#include "rpl_gtid.h"

 class Reprepare_observer;
 class Relay_log_info;
@ -3410,6 +3411,12 @@ private:
   */
  LEX_STRING invoker_user;
  LEX_STRING invoker_host;
+
+  /* Protect against add/delete of temporary tables in parallel replication */
+  void rgi_lock_temporary_tables();
+  void rgi_unlock_temporary_tables();
+  bool rgi_have_temporary_tables();
+public:
  /*
    Flag, mutex and condition for a thread to wait for a signal from another
    thread.
@ -3420,12 +3427,12 @@ private:
  bool wakeup_ready;
  mysql_mutex_t LOCK_wakeup_ready;
  mysql_cond_t COND_wakeup_ready;
+  /*
+     The GTID assigned to the last commit. If no GTID was assigned to any commit
+     so far, this is indicated by last_commit_gtid.seq_no == 0.
+  */
+  rpl_gtid last_commit_gtid;

-  /* Protect against add/delete of temporary tables in parallel replication */
-  void rgi_lock_temporary_tables();
-  void rgi_unlock_temporary_tables();
-  bool rgi_have_temporary_tables();
-public:
  inline void lock_temporary_tables()
  {
    if (rgi_slave)
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@ -3965,6 +3965,20 @@ rpl_deinit_gtid_slave_state()
 }


+void
+rpl_init_gtid_waiting()
+{
+  rpl_global_gtid_waiting.init();
+}
+
+
+void
+rpl_deinit_gtid_waiting()
+{
+  rpl_global_gtid_waiting.destroy();
+}
+
+
 /*
  Format the current GTID state as a string, for returning the value of
  @@global.gtid_slave_pos.
--- a/sql/sql_repl.h
+++ b/sql/sql_repl.h
@ -70,6 +70,8 @@ void mysql_binlog_send(THD* thd, char* log_ident, my_off_t pos, ushort flags);
 extern PSI_mutex_key key_LOCK_slave_state, key_LOCK_binlog_state;
 void rpl_init_gtid_slave_state();
 void rpl_deinit_gtid_slave_state();
+void rpl_init_gtid_waiting();
+void rpl_deinit_gtid_waiting();
 int gtid_state_from_binlog_pos(const char *name, uint32 pos, String *out_str);
 int rpl_append_gtid_state(String *dest, bool use_binlog);
 int rpl_load_gtid_state(slave_connection_state *state, bool use_binlog);
--- a/sql/sys_vars.cc
+++ b/sql/sys_vars.cc
@ -1538,6 +1538,33 @@ static Sys_var_gtid_binlog_state Sys_gtid_binlog_state(
       GLOBAL_VAR(opt_gtid_binlog_state_dummy), NO_CMD_LINE);


+static Sys_var_last_gtid Sys_last_gtid(
+       "last_gtid", "The GTID of the last commit (if binlogging was enabled), "
+       "or the empty string if none.",
+       READ_ONLY sys_var::ONLY_SESSION, NO_CMD_LINE);
+
+
+uchar *
+Sys_var_last_gtid::session_value_ptr(THD *thd, LEX_STRING *base)
+{
+  char buf[10+1+10+1+20+1];
+  String str(buf, sizeof(buf), system_charset_info);
+  char *p;
+  bool first= true;
+
+  str.length(0);
+  if ((thd->last_commit_gtid.seq_no > 0 &&
+       rpl_slave_state_tostring_helper(&str, &thd->last_commit_gtid, &first)) ||
+      !(p= thd->strmake(str.ptr(), str.length())))
+  {
+    my_error(ER_OUT_OF_RESOURCES, MYF(0));
+    return NULL;
+  }
+
+  return (uchar *)p;
+}
+
+
 static bool
 check_slave_parallel_threads(sys_var *self, THD *thd, set_var *var)
 {
--- a/sql/sys_vars.h
+++ b/sql/sys_vars.h
@ -2211,3 +2211,53 @@ public:
  }
  uchar *global_value_ptr(THD *thd, LEX_STRING *base);
 };
+
+
+/**
+  Class for @@session.last_gtid.
+*/
+class Sys_var_last_gtid: public sys_var
+{
+public:
+  Sys_var_last_gtid(const char *name_arg,
+          const char *comment, int flag_args, CMD_LINE getopt)
+    : sys_var(&all_sys_vars, name_arg, comment, flag_args, 0, getopt.id,
+              getopt.arg_type, SHOW_CHAR, 0, NULL, VARIABLE_NOT_IN_BINLOG,
+              NULL, NULL, NULL)
+  {
+    option.var_type= GET_STR;
+  }
+  bool do_check(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(false);
+    return true;
+  }
+  bool session_update(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(false);
+    return true;
+  }
+  bool global_update(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(false);
+    return true;
+  }
+  bool check_update_type(Item_result type) {
+    DBUG_ASSERT(false);
+    return false;
+  }
+  void session_save_default(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(false);
+  }
+  void global_save_default(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(false);
+  }
+  uchar *session_value_ptr(THD *thd, LEX_STRING *base);
+  uchar *global_value_ptr(THD *thd, LEX_STRING *base)
+  {
+    DBUG_ASSERT(false);
+    return NULL;
+  }
+};