I have just moved the web application into a new web server and new DB server. With the latest version of everything. However, when I run the application in live (with over 1000 users), I observe that every 2-3 minutes, there are slow query report. And when this happened, the php processes ( use 'top') shrink from 30 processes to a few or no processes. When that happened, there are sql connection error.
I have tried increase the max_connection and with different combination of buffer size. I even used the mysql tune-primeir to configure it in a reasonable way. However, it still behave kinda same way.
any idea what I should do and what I should watch out for the mysql / php configuration?