13.4.2.3 RESET SLAVE Statement

RESET SLAVE [ALL] [channel_option]

channel_option:
    FOR CHANNEL channel

RESET SLAVE makes the replica forget its replication position in the source's binary log. This statement is meant to be used for a clean start: It clears the replication metadata repositories, deletes all the relay log files, and starts a new relay log file. It also resets to 0 the replication delay specified with the MASTER_DELAY option to CHANGE MASTER TO.

Note

All relay log files are deleted, even if they have not been completely executed by the replication SQL thread. (This is a condition likely to exist on a replica if you have issued a STOP SLAVE statement or if the replica is highly loaded.)

For a server where GTIDs are in use (gtid_mode is ON), issuing RESET SLAVE has no effect on the GTID execution history. The statement does not change the values of gtid_executed or gtid_purged, or the mysql.gtid_executed table. If you need to reset the GTID execution history, use RESET MASTER, even if the GTID-enabled server is a replica where binary logging is disabled.

RESET SLAVE requires the RELOAD privilege.

To use RESET SLAVE, the replication threads must be stopped, so on a running replica use STOP SLAVE before issuing RESET SLAVE. To use RESET SLAVE on a Group Replication group member, the member status must be OFFLINE, meaning that the plugin is loaded but the member does not currently belong to any group. A group member can be taken offline by using a STOP GROUP REPLICATION statement.

The optional FOR CHANNEL channel clause enables you to name which replication channel the statement applies to. Providing a FOR CHANNEL channel clause applies the RESET SLAVE statement to a specific replication channel. Combining a FOR CHANNEL channel clause with the ALL option deletes the specified channel. If no channel is named and no extra channels exist, the statement applies to the default channel. Issuing a RESET SLAVE ALL statement without a FOR CHANNEL channel clause when multiple replication channels exist deletes all replication channels and recreates only the default channel. See Section 16.2.2, “Replication Channels” for more information.

RESET SLAVE does not change any replication connection parameters such as the source's host name and port, or the replication user account name and its password.

• From MySQL 5.7.24, when master_info_repository=TABLE is set on the server, replication connection parameters are preserved in the crash-safe InnoDB table mysql.slave_master_info as part of the RESET SLAVE operation. They are also retained in memory. In the event of an unexpected server exit or deliberate restart after issuing RESET SLAVE but before issuing START SLAVE, the replication connection parameters are retrieved from the table and reused for the new connection.

• When master_info_repository=FILE is set on the server (which is the default in MySQL 5.7), replication connection parameters are only retained in memory. If the replica mysqld is restarted immediately after issuing RESET SLAVE due to an unexpected server exit or deliberate restart, the connection parameters are lost. In that case, you must issue a CHANGE MASTER TO statement after the server start to respecify the connection parameters before issuing START SLAVE.

If you want to reset the connection parameters intentionally, you need to use RESET SLAVE ALL, which clears the connection parameters. In that case, you must issue a CHANGE MASTER TO statement after the server start to specify the new connection parameters.

RESET SLAVE causes an implicit commit of an ongoing transaction. See Section 13.3.3, “Statements That Cause an Implicit Commit”.

If the replication SQL thread was in the middle of replicating temporary tables when it was stopped, and RESET SLAVE is issued, these replicated temporary tables are deleted on the replica.

Prior to MySQL 5.7.5, RESET SLAVE also had the effect of resetting both the heartbeat period (Slave_heartbeat_period) and SSL_VERIFY_SERVER_CERT. This issue is fixed in MySQL 5.7.5 and later. (Bug #18777899, Bug #18778485)

Prior to MySQL 5.7.5, RESET SLAVE ALL did not clear the IGNORE_SERVER_IDS list set by CHANGE MASTER TO. In MySQL 5.7.5 and later, the statement clears the list. (Bug #18816897)

Note

When used on an NDB Cluster replica SQL node, RESET SLAVE clears the mysql.ndb_apply_status table. You should keep in mind when using this statement that ndb_apply_status uses the NDB storage engine and so is shared by all SQL nodes attached to the replica cluster.

You can override this behavior by issuing SET GLOBAL @@ndb_clear_apply_status=OFF prior to executing RESET SLAVE, which keeps the replica from purging the ndb_apply_status table in such cases.