Persistent connection's PROs and CONs ?

[terryds]

What is the advantage and disadvantage using persistent connection to MySQL database server ??

When to use it and when not to use it ?

[justsomeguy]

Connections have overhead. If you need to make a connection to the server every time someone pulls up a page then each page request will include that connection overhead. As far as the disadvantages go, there is a post here that discusses it:http://stackoverflow.com/questions/3332074/what-are-the-disadvantages-of-using-persistent-connection-in-pdo