The terms master and slave have historically been used in replication, but the
terms terms primary and replica are now preferred. The old terms are used
still used in parts of the documentation, and in MariaDB commands, although
MariaDB 10.5 has begun the process of renaming. The documentation process is
ongoing. See MDEV-18777 to follow progress on this effort.

Syntax
------

RESET REPLICA ["connection_name"] [ALL]  [FOR CHANNEL "connection_name"] --
from MariaDB 10.5.1         
RESET SLAVE ["connection_name"] [ALL]  [FOR CHANNEL "connection_name"]

Description
-----------

RESET REPLICA/SLAVE makes the replica forget its replication position in the
master's binary log. This statement is meant to be used for a clean start. It
deletes the master.info and relay-log.info files, all the relay log files, and
starts a new relay log file. To use RESET REPLICA/SLAVE, the replica threads
must be stopped (use STOP REPLICA/SLAVE if necessary).

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

Note: RESET REPLICA does not reset the global gtid_slave_pos variable. This
means that a replica server configured with CHANGE MASTER TO
MASTER_USE_GTID=slave_pos will not receive events with GTIDs occurring before
the state saved in gtid_slave_pos. If the intent is to reprocess these events,
gtid_slave_pos must be manually reset, e.g. by executing set global
gtid_slave_pos="".

Connection information stored in the master.info file is immediately reset
using any values specified in the corresponding startup options. This
information includes values such as master host, master port, master user, and
master password. If the replica SQL thread was in the middle of replicating
temporary tables when it was stopped, and RESET REPLICA/SLAVE is issued, these
replicated temporary tables are deleted on the slave.

The ALL also resets the PORT, HOST, USER and PASSWORD parameters for the
slave. If you are using a connection name, it will permanently delete it and
it will not show up anymore in SHOW ALL REPLICAS/SLAVE STATUS.

connection_name
---------------

The connection_name option is used for multi-source replication.

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 RESET REPLICA/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 RESET REPLICA.

RESET REPLICA
-------------

MariaDB starting with 10.5.1
----------------------------
RESET REPLICA is an alias for RESET SLAVE from MariaDB 10.5.1.

URL: https://mariadb.com/kb/en/reset-replica/