check mysql lagtime (Visit this link)

Check connection an check show status values. Some plugins for checking predefined values and one generic for checking the values given on the commandline.

Plugin written in C which allows to monitor various performance-related characteristics of a MySQL database.

Plugin that checks for various performance stats from MySQL

Replacement for check_mysql that allows to set thresholds for any variables in SHOW STATUS or for similar SQL queries. Data is also made available for graphing or other use (graphing templates enclosed)

check_mysql_health is a plugin for Nagios that allows you to monitor a MySQL database. Among the list of metrics are time to login, index usage, bufferpool hit rate, query cache hit rate, slow queries, temp tables on disk, table cache hit rate, connected threads, and many more. Requirements are either a DBD::mysql Perl module or a MySQL client package.

checks to see if mysql slave io is running. written in a shell script, so its easily portable.

Check row count in table. Possible to specify WHERE conditionals.

Plugin to check the number of active nodes that aren't in a down or disconnected state from your NDB cluster. Has fully customizable prefixing, commands, and thresholds from the command-line or nagios command definitions. Uses the 'ndb_mgm -e show' command to gather the data.

Checks the number of client connections currently established towards a specified MySQL database server.