I don't see the point of implementing an own PDO-like interface, since PDO is fast enough, feature rich and imho is the future of low level DB abstraction in PHP. A higher level abstraction (eg. ORMs) is too complex and slow for such an application.
About the persistent connections... I think you should not use keepalives. Just reconnect again if connection is lost. The only time penalty is present when you have to use some remote TCP/IP connections but typically the databases run localhost. Using unix domain sockects provide quasi immediate connections. Anyway, extending PDO leaves space for implementing keepalives if you wish to.
About the persistent connections... I think you should not use keepalives. Just reconnect again if connection is lost. The only time penalty is present when you have to use some remote TCP/IP connections but typically the databases run localhost. Using unix domain sockects provide quasi immediate connections. Anyway, extending PDO leaves space for implementing keepalives if you wish to.