In the current project I'm working on I see a lot of developers making the mistake of caching date filtered queries.
Why shouldn't you cache date filtered queries? 1. If you're filtering by the current moment in time then the results are irrelevant within a few moments of them being retrieved. Some records may be due to expire and others (that were filtered out) may be about to become active. 2. Despite what I say in #1, there's a bug in the equals method of EntityDateFilterCondition where all instances appear equal so the cached result is never replaced until it is expired from the cache. So expired records remain and future dated records never appear until the TTL is reached. The correct approach is to not have a date filter in the query, cache the result and then filter the result in-memory using EntityUtil.filterByDate(). An alternative approach is to only filter by thruDate in the query since expired records will never become active, and then filter by fromDate after you have the result. We have no utility tools in place for the latter approach though. I'm writing all this because I've written a checker for the entity list and object caches that inspect the query conditions for fromDate conditions and if found, log a warning and refuse to cache. I'd like to add this safety feature to the OFBiz trunk but I'm wondering if anyone can think of a valid reason to cache fromDate filtered records? I haven't been able to think of any but that doesn't necessarily mean there aren't any use cases. Thanks Scott
