People often say things like "application X is write heavy", 20/80 write vs reads, etc.
What metric(s) is most relevant for MySQL when checking if an application is write/read heavy?
Is checking Com_insert, etc enough, not taking into account number of rows read/modified, or is it checking iostat metrics?
Best Answer
An application being read/write heavy is subject to interpretation based on the following:
These things are meant to measure SQL command counts and the amount of data passing here and there. There are other metrics within the InnoDB storage engine that should be monitored and tuned so that any write heavy behavior is improved.
Rather than name those features of InnoDB, please go to the Server Status Variables page and look for any status variable mentioning the Redo Log Writes and Buffer Pool read/writes.