SQL Statements for Controlling Replica Servers START {REPLICA | SLAVE} UNTIL SQL_AFTER_MTS_GAPS; SET @@GLOBAL.slave_parallel_workers = 0; START {REPLICA | SLAVE} SQL_THREAD; Note It is possible to view the entire text of a running  START REPLICA | SLAVE statement, including any  USER  or  PASSWORD  values used, in the output of  SHOW PROCESSLIST . This is also true for the text of a running  CHANGE REPLICATION SOURCE TO  |  CHANGE MASTER TO  statement, including any values it employs for SOURCE_USER  |  MASTER_USER  or  SOURCE_PASSWORD  |  MASTER_PASSWORD . START REPLICA | SLAVE  sends an acknowledgment to the user after both the replication I/O thread and the replication SQL thread have started. However, the replication I/O thread may not yet have connected. For this reason, a successful  START REPLICA | SLAVE  causes  SHOW REPLICA | SLAVE STATUS to show  Replica_SQL_Running=Yes , but this does not guarantee that  Replica_IO_Running=Yes (because  Replica_IO_Running=Yes  only if the I/O thread is running  and connected ). For more information, see Section 13.7.7.35, “SHOW REPLICA | SLAVE STATUS Statement” , and Section 17.1.7.1, “Checking Replication Status” . An  UNTIL  clause ( until_option , in the preceding grammar) may be added to specify that the replica should start and run until the replication SQL thread reaches a given point in the source’s binary log or in the replica’s relay log. Use one of the following pairs of options to specify the position: • MASTER_LOG_POS  and  MASTER_LOG_FILE  for the binary log (to MySQL 8.0.22). • SOURCE_LOG_POS  and  SOURCE_LOG_FILE  for the binary log (from MySQL 8.0.23). • RELAY_LOG_POS  and  RELAY_LOG_FILE  for the relay log. For compressed transaction payloads, the position must be based on the compressed Transaction_payload_event . When the SQL thread reaches the point specified, it stops. If the SQL_THREAD  option is specified in the statement, it starts only the SQL thread. Otherwise, it starts both replication threads. If the SQL thread is running, the  UNTIL  clause is ignored and a warning is issued. You cannot use an  UNTIL  clause with the  IO_THREAD  option. It is also possible with  START REPLICA | SLAVE UNTIL  to specify a stop point relative to a given GTID or set of GTIDs using one of the options  SQL_BEFORE_GTIDS  or  SQL_AFTER_GTIDS , as explained previously in this section. When using one of these options, you can specify  SQL_THREAD ,  IO_THREAD , both of these, or neither of them. If you specify only  SQL_THREAD , then only the replication SQL thread is affected by the statement; if only  IO_THREAD  is used, then only the replication I/O thread is affected. If both  SQL_THREAD  and  IO_THREAD  are used, or if neither of them is used, then both the SQL and I/O threads are affected by the statement. For an  UNTIL  clause, you must specify any one of the following: Do not mix source and relay log options. Do not mix log file options with GTID options. The  UNTIL  clause is not supported for multithreaded replicas except when also using SQL_AFTER_MTS_GAPS . If  UNTIL  is used on a multithreaded replica without  SQL_AFTER_MTS_GAPS , the • Both  a log file name and a position in that file • Either  of  SQL_BEFORE_GTIDS  or  SQL_AFTER_GTIDS • SQL_AFTER_MTS_GAPS 2778