Oracle Datasource returning null connection

Question

The oracle data source is returning null connection when the no of connection request is more. I have the implict cache enabled.The oracle specs says null is returned only is ConnectionWaitTimeout is set. I do not have a value set for ConnectionWaitTimeout in the cache properties.

This is what the spec says about

ConnectionWaitTimeout

Specifies cache behavior when a connection is requested and there are already MaxLimit connections active. If ConnectionWaitTimeout is greater than zero, then each connection request waits for the specified number of seconds or until a connection is returned to the cache. If no connection is returned to the cache before the timeout elapses, then the connection request returns null.

Default: 0 (no timeout)

What are other possiblies where the Datasource could return a null connection?

Answer 1

I think the default may vary depending on what version of Oracle you are using. Some of the information is contradictory, e.g. Oracles "Optimizing Connection Pool Behavior" implies the default is 3 seconds (11g?) wheras other sources state that it is zero as mentioned in the question.

I'd suggest explicitly setting it to zero and see if the behavior still manifests itself.