Merge branch 'mdev10863' into 10.0

mysql-test/suite/rpl/r/rpl_mdev10863.result

+include/rpl_init.inc [topology=1->2]
+SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
+include/stop_slave.inc
+SET GLOBAL slave_parallel_threads=10;
+SET @old_max_relay= @@GLOBAL.max_relay_log_size;
+SET GLOBAL max_relay_log_size = 4096;
+CHANGE MASTER TO master_use_gtid=slave_pos;
+include/start_slave.inc
+ALTER TABLE mysql.gtid_slave_pos ENGINE=InnoDB;
+CREATE TABLE t1 (a int PRIMARY KEY, b VARCHAR(100)) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (1, "a");
+*** Create a long transaction that will span a relay log file. ***
+SET @old_domain= @@gtid_domain_id;
+SET gtid_domain_id=10;
+INSERT INTO t1 VALUES (10000, "domain 10");
+SET gtid_domain_id=20;
+INSERT INTO t1 VALUES (20000, "domain 20");
+SET gtid_domain_id=@old_domain;
+BEGIN;
+[lots of inserts omitted]
+COMMIT;
+BEGIN;
+[lots of inserts omitted]
+COMMIT;
+include/stop_slave_sql.inc
+START SLAVE SQL_THREAD;
+include/wait_for_slave_to_start.inc
+INSERT INTO t1 VALUES (100000, "More stuffs.");
+INSERT INTO t1 VALUES (100001, "And even more");
+SELECT * FROM t1 WHERE a >= 100000 ORDER BY a;
+a	b
+100000	More stuffs.
+100001	And even more
+include/stop_slave.inc
+SET GLOBAL slave_parallel_threads=@old_parallel_threads;
+SET GLOBAL max_relay_log_size= @old_max_relay;
+include/start_slave.inc
+DROP TABLE t1;
+include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_mdev10863.test

+--source include/have_innodb.inc
+--let $rpl_topology=1->2
+--source include/rpl_init.inc
+
+# Test various aspects of parallel replication.
+
+--connection server_2
+SET @old_parallel_threads=@@GLOBAL.slave_parallel_threads;
+--source include/stop_slave.inc
+SET GLOBAL slave_parallel_threads=10;
+SET @old_max_relay= @@GLOBAL.max_relay_log_size;
+SET GLOBAL max_relay_log_size = 4096;
+CHANGE MASTER TO master_use_gtid=slave_pos;
+--source include/start_slave.inc
+
+--connection server_1
+ALTER TABLE mysql.gtid_slave_pos ENGINE=InnoDB;
+CREATE TABLE t1 (a int PRIMARY KEY, b VARCHAR(100)) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (1, "a");
+--save_master_pos
+
+--connection server_2
+--sync_with_master
+
+--echo *** Create a long transaction that will span a relay log file. ***
+--connection server_1
+
+# Add some transactions in separate domains, that will cause the need to
+# have a multi-valued restart position in the relay log for the SQL thread.
+SET @old_domain= @@gtid_domain_id;
+SET gtid_domain_id=10;
+INSERT INTO t1 VALUES (10000, "domain 10");
+SET gtid_domain_id=20;
+INSERT INTO t1 VALUES (20000, "domain 20");
+SET gtid_domain_id=@old_domain;
+
+BEGIN;
+--echo [lots of inserts omitted]
+--disable_query_log
+--let $count = 500
+while ($count) {
+  eval INSERT INTO t1 VALUES (1000+$count, REPEAT("hulubulu??!?", 8));
+  dec $count;
+}
+--enable_query_log
+COMMIT;
+
+--save_master_pos
+
+--connection server_2
+--sync_with_master
+
+--connection server_1
+# Now do another one, to make the inuse_relaylog proceed to somewhere inside
+# the first large transaction.
+
+BEGIN;
+--echo [lots of inserts omitted]
+--disable_query_log
+--let $count = 500
+while ($count) {
+  eval INSERT INTO t1 VALUES (2000+$count, REPEAT("hulubulu??!?", 8));
+  dec $count;
+}
+--enable_query_log
+COMMIT;
+
+--save_master_pos
+
+--connection server_2
+--sync_with_master
+
+
+# Stop and restart the SQL thread only.
+# The bug was that the SQL thread would restart at the start
+# of a relay log file, which could be in the middle of an event group.
+# This way, part of that event group could be wrongly re-applied.
+
+--source include/stop_slave_sql.inc
+START SLAVE SQL_THREAD;
+--source include/wait_for_slave_to_start.inc
+
+
+--connection server_1
+INSERT INTO t1 VALUES (100000, "More stuffs.");
+INSERT INTO t1 VALUES (100001, "And even more");
+--save_master_pos
+
+--connection server_2
+--sync_with_master
+SELECT * FROM t1 WHERE a >= 100000 ORDER BY a;
+
+
+# Clean up.
+--connection server_2
+--source include/stop_slave.inc
+SET GLOBAL slave_parallel_threads=@old_parallel_threads;
+SET GLOBAL max_relay_log_size= @old_max_relay;
+--source include/start_slave.inc
+
+--connection server_1
+DROP TABLE t1;
+
+--source include/rpl_end.inc

sql/slave.cc

@@ -4546,6 +4546,21 @@ pthread_handler_t handle_slave_sql(void *arg)
 
   serial_rgi->gtid_sub_id= 0;
   serial_rgi->gtid_pending= false;
+  if (mi->using_gtid != Master_info::USE_GTID_NO &&
+      opt_slave_parallel_threads > 0 &&
+      rli->restart_gtid_pos.count() > 0)
+  {
+    /*
+      With parallel replication in GTID mode, if we have a multi-domain GTID
+      position, we need to start some way back in the relay log and skip any
+      GTID that was already applied before. Since event groups can be split
+      across multiple relay logs, this earlier starting point may be in the
+      middle of an already applied event group, so we also need to skip any
+      remaining part of such group.
+    */
+    rli->gtid_skip_flag = GTID_SKIP_TRANSACTION;
+  }
+  else
     rli->gtid_skip_flag = GTID_SKIP_NOT;
   if (init_relay_log_pos(rli,
                          rli->group_relay_log_name,