Here are the things I can't change: We got a mySQL myISAM replication running a master and some slaves. One slave is being used for nightly backups using mysqldump. The backups is using heavy locks forcing it's slave to "age" compared to the master. mysqldump is connecting as root dumping all the databases while every other connection is using one non-SUPER-user per database. The dumps are started using a simple shell script on a dedicated backup server.
Here is the problem: I'ld like to detect if a backup is running or not while being connected as a "normal" user to one of the databases running on the server being backuped. Cronjobs should be able to react on the running backup by exiting early or processing only really important required jobs which can't wait until the backup is done. The server running the backup script has no connections to the webservers, their only common point is the mysql server. The backup script could do some things to flag the server as "currently running a backup". I'd prefer to set some kind of "global server-side environment variable visible by all users" to ignore only the one slave running the backup but it would also be ok to simply know that a backup is running on that database or replication chain. Using the database for this is no option as it's being locked during the backup.
I tried to create a temp table on backup start (existing = backup is running, not existing = no backup running), but temp tables only show up for the connection which originally created it (as expected). I googled if a non-SUPER-user could get the permission to see the SHOW PROCESSLIST of all connections including other users and root (any connection from the backup server = backup is running) - but no luck. Giving SUPER to all database users is no option.
Thanks for reading (and answering).