MySQL can be monitored via SNMP with the free Mysql-snmp module by Brice Figureau. There are many counters available under:
But did you notice that (??) node in the counter path? That's because of how the MySQL MIB file is defined. Depending on what application you use for SNMP monitoring (it should be PA Server Monitor!!) it may have problems getting from the enterprises node to the mySQL node. This might be considered a MYSQL-SERVER.mib error.
This can be easily fixed with a small change to the MYSQL-SERVER.mib file.
Change this line:
Now that unnamed node has a name (mySQLRoot) most SNMP applications will be able to parse and traverse the MIB without problems.
Make sure the changed MIB file is in:
C:\Program Files\PA Server Monitor\MIBs
and restart the monitoring service so the changed MIB file is reparsed.