MySQL 9.5 Reference Manual Including MySQL NDB Cluster 9.5
When a replica has multiple channels and a FOR CHANNEL
option is not
specified, a valid statement generally acts on all available
channels, with some specific exceptions.
channel
For example, the following statements behave as expected for all except certain Group Replication channels:
START REPLICA starts
replication threads for all channels, except the
group_replication_recovery and
group_replication_applier channels.
STOP REPLICA stops replication
threads for all channels, except the
group_replication_recovery and
group_replication_applier channels.
SHOW REPLICA STATUS reports the
status for all channels, except the
group_replication_applier channel.
RESET REPLICA resets all
channels.
Use RESET REPLICA with caution as
this statement deletes all existing channels, purges their relay
log files, and recreates only the default channel.
Some replication statements cannot operate on all channels. In
this case, error 1964 Multiple channels exist on the
replica. Please provide channel name as an argument.
is generated. The following statements and functions generate this
error when used in a multi-source replication topology and a
FOR CHANNEL
option is not used to specify which channel to act on:
channel
Note that a default channel always exists in a single source replication topology, where statements and functions behave as in previous versions of MySQL.