Dev's, We've had a few regression-type issues (OPENJPA-660 & OPENJPA-731) since the addition of QuerySQLCache in 1.2.0. While this cache has shown to provide significant performance improvements for certain scenarios, I think we should consider disabling the cache by default. The main reason is the potential for future regression issues. Another reason is that we didn't follow the pattern set by existing caches. With the exception of the query compilation cache (which is relatively static after queries are initialized), the other caches are disabled by default. While the cache is supposed to be transparent, it could (and has shown to) affect the behavior of an application that has been working for quite some time on a prior release.
Arguably, QuerySQLCache may just need more rigorous testing. While additional testing may help, testing every scenario is difficult and if we miss one, regression issues due to performance enhancements are pretty hard to swallow. I think a better approach is to allow users to enable the cache if they choose to do so. What do y'all think? If we get a consensus, I'll open an issue to make the necessary changes to disable the cache. -Jeremy
