MySQL monitoring tools

What tools do you use to monitor the health of your MySQL server instance? Are they for free or commercial?

Try MySQL Cacti Templates.

mytop provides some handy CLI info, it's free (*unix only).

Mysql has a free one called Mysql Administrator which is part of the mysql GUI tools package.

Mysql Administrator connection documentation.

There is also the Mysql Enterprise Monitor which has many more monitoring features. You can monitor Mysql on other servers see faq question 7.

I like SQLyog for remote administration of mySQL. Nice GUI environment, and there is a free community edition.

This company also makes MONyog, a mySQL monitoring solution, but it's not free and I haven't played with it.

I have a custom Zabbix configuration for extracting useful data points from MySQL. I should get around to opening these scripts up to the community.