Syntax:
RESET REPLICA [ALL] [channel_option]

channel_option:
    FOR CHANNEL channel

RESET REPLICA makes the replica forget its position in the source's
binary log. From MySQL 8.0.22, use RESET REPLICA in place of RESET
SLAVE, which is deprecated from that release. In releases before MySQL
8.0.22, use RESET SLAVE.

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 SOURCE_DELAY | MASTER_DELAY option of the CHANGE
REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER TO
statement (before MySQL 8.0.23).

*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 REPLICA statement or if
the replica is highly loaded.)

For a server where GTIDs are in use (gtid_mode is ON), issuing RESET
REPLICA 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 REPLICA requires the RELOAD privilege.

To use RESET REPLICA, the replication SQL thread and replication I/O
(receiver) thread must be stopped, so on a running replica use STOP
REPLICA before issuing RESET REPLICA. To use RESET REPLICA 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 REPLICA 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 REPLICA ALL statement without a FOR CHANNEL channel
clause when multiple replication channels exist deletes all replication
channels and recreates only the default channel. See
https://dev.mysql.com/doc/refman/8.0/en/replication-channels.html for
more information.

RESET REPLICA does not change any replication connection parameters,
which include the source's host name and port, the replication user
account and its password, the PRIVILEGE_CHECKS_USER account, the
REQUIRE_ROW_FORMAT option, the REQUIRE_TABLE_PRIMARY_KEY_CHECK
option,and the ASSIGN_GTIDS_TO_ANONYMOUS_TRANSACTIONS option. If you
want to change any of the replication connection parameters, you can do
this using a CHANGE REPLICATION SOURCE TO statement (from MySQL 8.0.23)
or CHANGE MASTER TO statement (before MySQL 8.0.23) after the server
start. If you want to remove all of the replication connection
parameters, use RESET REPLICA ALL. RESET REPLICA ALL also clears the
IGNORE_SERVER_IDS list set by CHANGE REPLICATION SOURCE TO | CHANGE
MASTER TO. When you have used RESET REPLICA ALL, if you want to use the
instance as a replica again, you need to issue a CHANGE REPLICATION
SOURCE TO | CHANGE MASTER TO statement after the server start to
specify new connection parameters.

From MySQL 8.0.27, you can set the GTID_ONLY option on the CHANGE
REPLICATION SOURCE TO statement to stop a replication channel from
persisting file names and file positions in the replication metadata
repositories. When you issue a RESET REPLICA statement, the replication
metadata repositories are synchronized. RESET REPLICA ALL deletes
rather than updates the repositories, so they are synchronized
implicitly.

In the event of an unexpected server exit or deliberate restart after
issuing RESET REPLICA but before issuing START REPLICA, retention of
the replication connection parameters depends on the repository used
for the replication metadata:

o When master_info_repository=TABLE and relay_log_info_repository=TABLE
  are set on the server (which are the default settings from MySQL
  8.0), replication connection parameters are preserved in the
  crash-safe InnoDB tables mysql.slave_master_info and
  mysql.slave_relay_log_info as part of the RESET REPLICA operation.
  They are also retained in memory. In the event of an unexpected
  server exit or deliberate restart after issuing RESET REPLICA but
  before issuing START REPLICA, the replication connection parameters
  are retrieved from the tables and reapplied to the channel. This
  situation applies from MySQL 8.0.13 for the connection metadata
  repository, and from MySQL 8.0.19 for the applier metadata
  repository.

o If master_info_repository=FILE and relay_log_info_repository=FILE are
  set on the server, which is deprecated from MySQL 8.0, or the MySQL
  Server release is earlier than those specified above, replication
  connection parameters are only retained in memory. If the replica
  mysqld is restarted immediately after issuing RESET REPLICA due to an
  unexpected server exit or deliberate restart, the connection
  parameters are lost. In that case, you must issue a CHANGE
  REPLICATION SOURCE TO statement (from MySQL 8.0.23) or CHANGE MASTER
  TO statement (before MySQL 8.0.23) after the server start to
  respecify the connection parameters before issuing START REPLICA.

RESET REPLICA does not change any replication filter settings (such as
--replicate-ignore-table) for channels affected by the statement.
However, RESET REPLICA ALL removes the replication filters that were
set on the channels deleted by the statement. When the deleted channel
or channels are recreated, any global replication filters specified for
the replica are copied to them, and no channel specific replication
filters are applied. For more information see
https://dev.mysql.com/doc/refman/8.0/en/replication-rules-channel-based
-filters.html.

RESET REPLICA causes an implicit commit of an ongoing transaction. See
https://dev.mysql.com/doc/refman/8.0/en/implicit-commit.html.

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

*Note*:

When used on an NDB Cluster replica SQL node, RESET REPLICA 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 cluster.

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

URL: https://dev.mysql.com/doc/refman/8.0/en/reset-replica.html

