The following list shows the most common states you may see in
the State column for a slave server SQL
thread:
Waiting for the next event in relay log
The initial state before Reading event from the
relay log.
Reading event from the relay log
The thread has read an event from the relay log so that the event can be processed.
The thread is executing a
LOAD DATA
INFILE statement and is creating a temporary file
containing the data from which the slave will read rows.
Slave has read all relay log; waiting for the slave
I/O thread to update it
The thread has processed all events in the relay log files, and is now waiting for the I/O thread to write new events to the relay log.
Waiting for slave mutex on exit
A very brief state that occurs as the thread is stopping.
The State column for the I/O 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 is executing it.