I was recently struck by a problem which is unusual. In order to
keep an eye on the database server I use nagios, cacti, merlin and some local scripts to monitor the
database instance and ensure that it is working properly.
That normally works fine. The different monitor processes
do various things, one of which is to monitor the replication
status of a slave, and warn me if the replication is not working
or if it’s behind. This is done with the command
SHOW SLAVE …