An improved method, mechanism, and system for implementing, generating, and maintaining for implementing session pools is disclosed. Disclosed is a method, mechanism, and system for dynamic sizing of session pools, in which the number of sessions in a given session pool or sub-session pool can be dynamically adjusted upwards or downwards. Also disclosed is an approach for customizing a session in a session pool with a specific set of affinities and attributes, in which tags can be associated with the customized sessions. Tagging can be used to identify sessions to deallocate/reallocate to dynamically size the session or sub-session pools.