Talk:EclipseLink/DesignDocs/214661

Feedback

Default

I'm not sure this new mode should be the default. For one it seems highly experimental, and perhaps not something we want to introduce as the default close to a release. But more importantly it breaks the transactional cache. If you read any object once it an EntityManager, then re-read it again, it will no longer be in the transactional cache, and will need to be re-built, if you use an isolated cache, then it will need to be re-queried from the database. James.sutherland.oracle.com 08:53, 24 April 2008 (EDT)

Performance

Adding weak references all over the unit of work seems like it will add significant performance overhead. Also even in the HARD mode it seems that the checks for this will add significant performance overhead. This performance impact of this feature should be measure in detail. Also the uow currently uses an optimized identity map class that avoids all of the locking overhead of the session maps, switching to weak identity map will remove this optimization. James.sutherland.oracle.com 08:53, 24 April 2008 (EDT)

Reference Queues

Using reference queues in weak identity maps is an intriguing idea. Avoiding the large performance bottleneck of the cleanup would be very desirable. I would like to see how this will work discussed more in this document. Also performance impact should be measure to see if there is a positive or negative improvement, if negative then this should not be implemented.