START SLAVE
The terms master and slave have historically been used in replication, and MariaDB has begun the process of adding primary and replica synonyms. The old terms will continue to be used to maintain backward compatibility - see MDEV-18777 to follow progress on this effort.
Syntax
START SLAVE ["connection_name"] [thread_type [, thread_type] ... ] [FOR CHANNEL "connection_name"]
START SLAVE ["connection_name"] [SQL_THREAD] UNTIL
MASTER_LOG_FILE = 'log_name', MASTER_LOG_POS = log_pos [FOR CHANNEL "connection_name"]
START SLAVE ["connection_name"] [SQL_THREAD] UNTIL
RELAY_LOG_FILE = 'log_name', RELAY_LOG_POS = log_pos [FOR CHANNEL "connection_name"]
START SLAVE ["connection_name"] [SQL_THREAD] UNTIL
MASTER_GTID_POS = <GTID position> [FOR CHANNEL "connection_name"]
START ALL SLAVES [thread_type [, thread_type]]
START REPLICA ["connection_name"] [thread_type [, thread_type] ... ] -- from 10.5.1
START REPLICA ["connection_name"] [SQL_THREAD] UNTIL
MASTER_LOG_FILE = 'log_name', MASTER_LOG_POS = log_pos -- from 10.5.1
START REPLICA ["connection_name"] [SQL_THREAD] UNTIL
RELAY_LOG_FILE = 'log_name', RELAY_LOG_POS = log_pos -- from 10.5.1
START REPLICA ["connection_name"] [SQL_THREAD] UNTIL
MASTER_GTID_POS = <GTID position> -- from 10.5.1
START ALL REPLICAS [thread_type [, thread_type]] -- from 10.5.1
thread_type: IO_THREAD | SQL_THREAD
Contents
Description
START SLAVE (START REPLICA from MariaDB 10.5.1) with no thread_type options starts both of the replica threads (see replication) needed to connect with a master setup with CHANGE MASTER TO .
The I/O thread reads events from the primary server and stores
them in the relay log. The SQL thread reads events from the relay log
and executes them. START SLAVE requires the SUPER privilege, or, from MariaDB 10.5.2, the REPLICATION SLAVE ADMIN privilege.
If START SLAVE succeeds in starting the replica threads, it returns
without any error. However, even in that case, it might be that the
replica threads start and then later stop (for example, because they do
not manage to connect to the primary or read its binary log, or some
other problem). START SLAVE does not warn you about this. You must
check the replica's error log for error messages generated by the replica
threads, or check that they are running satisfactorily with SHOW SLAVE
STATUS (SHOW REPLICA STATUS from MariaDB 10.5.1).
START SLAVE UNTIL
START SLAVE UNTIL refers to the SQL_THREAD replica position at which the SQL_THREAD replication will halt. If SQL_THREAD isn't specified both threads are started.
START SLAVE UNTIL master_gtid_pos=xxx is also supported. See Global Transaction ID/START SLAVE UNTIL master_gtid_pos=xxx for more details.
MariaDB starting with 11.3.0
SQL_BEFORE_GTIDS|SQL_AFTER_GTIDS
MariaDB 11.3 extended the START SLAVE UNTIL command with the options SQL_BEFORE_GTIDS and SQL_AFTER_GTIDS to allow control of whether the replica stops before or after a provided GTID state. Its
syntax is:
START SLAVE UNTIL (SQL_BEFORE_GTIDS|SQL_AFTER_GTIDS)="<gtid_list>"
See Global Transaction ID#SQL_BEFORE_GTIDS/SQL_AFTER_GTIDS for details.
connection_name
If there is only one nameless primary, or the default primary (as specified by the default_master_connection system variable) is intended, connection_name can be omitted. If provided, the START SLAVE statement will apply to the specified primary. connection_name is case-insensitive.
MariaDB starting with 10.7.0
The FOR CHANNEL keyword was added for MySQL compatibility. This is identical as
using the channel_name directly after START SLAVE.
START ALL SLAVES
START ALL SLAVES starts all configured replicas (replicas with master_host not empty) that were not started before. It will give a note for all started connections. You can check the notes with SHOW WARNINGS.
START REPLICA
MariaDB starting with 10.5.1
START REPLICA is an alias for START SLAVE from MariaDB 10.5.1.
See Also
- Setting up replication.
- CHANGE MASTER TO is used to create and change connections.
- STOP SLAVE is used to stop a running connection.
- RESET SLAVE is used to reset parameters for a connection and also to permanently delete a primary connection.
