MySQL 9.5 Reference Manual Including MySQL NDB Cluster 9.5
        The following list shows the most common states you may see in
        the State column for a replication SQL thread
        on a replica server.
      
        Set the
        terminology_use_previous system
        variable with session scope to support individual functions, or
        global scope to be a default for all new sessions. When global
        scope is used, the slow query log contains the old versions of
        the names.
      
            
            
            Making temporary file (append) before replaying
            LOAD DATA INFILE
          
            The thread is executing a LOAD
            DATA statement and is appending the data to a
            temporary file containing the data from which the replica
            reads rows.
          
            
            
            Making temporary file (create) before replaying
            LOAD DATA INFILE
          
            The thread is executing a LOAD
            DATA statement and is creating a temporary file
            containing the data from which the replica reads rows. This
            state can only be encountered if the original
            LOAD DATA statement was
            logged by a source running a version of MySQL lower than
            MySQL 5.0.3.
          
            
            
            Reading event from the relay log
          
The thread has read an event from the relay log so that the event can be processed.
            
            
            Slave has read all relay log; waiting for more
            updates
          
            
            
            Replica has read all relay log; waiting for more
            updates
          
The thread has processed all events in the relay log files, and is now waiting for the I/O (receiver) thread to write new events to the relay log.
            
            
            Waiting for an event from Coordinator
          
            Using the multithreaded replica
            (replica_parallel_workers
            is greater than 1), one of the replica worker threads is
            waiting for an event from the coordinator thread.
          
            
            
            Waiting for slave mutex on exit
          
            
            
            Waiting for replica mutex on exit
          
A very brief state that occurs as the thread is stopping.
            
            
            Waiting for Slave Workers to free pending
            events
          
            
            
            Waiting for Replica Workers to free pending
            events
          
            This waiting action occurs when the total size of events
            being processed by Workers exceeds the size of the
            replica_pending_jobs_size_max
            system variable. The Coordinator resumes scheduling when the
            size drops below this limit.
            
          
            
            
            Waiting for the next event in relay log
          
            The initial state before Reading event from the
            relay log.
          
            
            
            Waiting until SOURCE_DELAY seconds after source
            executed event
          
            The SQL thread has read an event but is waiting for the
            replica delay to lapse. This delay is set with the
            SOURCE_DELAY option of the
            CHANGE REPLICATION SOURCE TO.
          
        The Info column for the SQL thread may also
        show the text of a statement. This indicates that the thread has
        read an event from the relay log, extracted the statement from
        it, and may be executing it.