[hibernate-dev] Cache key containing composite ID with a many-to-one

When an entity is cached with a composite ID containing a many-to-one association, the cache key will contain the many-to-one associated entity. If the associated entity is not enhanced, then it could be an uninitialized proxy. I've created a test case [1] that illustrates this using Infinispan. The test case is for 5.1 branch, since hibernate-infinispan is still included in that branch. The same would happen for master as well. Aside from the obvious issue with increased memory requirements to store an entity, there are other problems as well. What I've found so far is that caching a key with an uninitialized entity proxy can cause some big problems: 1) A lookup will never find this key unless the lookup is done with a cache key containing the same entity proxy instance. 2) Calling EntityManager#find with a composite ID containing a detached uninitialized entity proxy will result in a LazyInitializationException. This does not happen with second-level cache disabled. 3) Calling EntityManager#find with a composite ID containing a managed uninitialized entity proxy will result in the proxy being initialized. This does not happen with second-level cache disabled. I have not looked into what happens when the associated entity is enhanced and uninitialized (i.e., enhancement-as-proxy). IIUC, disassembling the ID that gets stored in the cache key would be far more efficient, and would avoid these issues. We would only want to do this when a composite ID contains an association. This would require changes in some SPIs though, to account for the disassembled ID type. I've been discussing necessary changes with Scott to cache a disassembled ID. Before we get too far down this road, I'd like to get some feedback. In the first place, should an entity instance be stored in a cache key? Is disassembling primary keys that contain an association the appropriate way to go? If so, I'll continue with a POC for doing this. Thanks, Gail [1] https://github.com/gbadner/hibernate-core/blob/753e36edf5137296d28b2a07ce...