A useful diagnostic tool called `mysqlslap` comes with MySQL (since version 5.1.4).
It is a benchmarking tool that can emulate a large number of client connections hitting the database server at the same time.
Although most uses on Acquia Cloud itself are prohibited, except those on dedicated hardware (see Load and stress testing) this tool can help with load testing on local and dedicated environments.
Developers can use this important tool to create tests under load on the database server and hence develop more robust code. Such code has a better chance of surviving past the next high-traffic time after it is pushed to Acquia Cloud Prod, since it can be tested since inception (and locally) in the presence of database server load.