On his blog today, Christopher Jones hands the floor off to Luxi Chidambaran to talk some about "Highly Scalable Connection Pooling in PHP".
Oracle Database Resident Connection Pooling - a connection pooling feature in the next version of the Oracle DB that will allow very high traffic web sites to scale better. We announced this feature at Oracle OpenWorld in 2006. One cool thing about the feature is that it is not just limited to PHP - any database client could use it.
Luxi talks about pooling in general, pooling database connections specifically, how Oracle handles it and the three views around it - DBA, Client side, and the PHP user views.