Release Notes: This release introduces an extensive caching module that offers three levels of granularity (page, action, fragment) and a variety of stores (file, memory, DRb, MemCached). Additionally, it's now possible to limit the actions that a given filter will apply to within a controller using either :only or : except. Associations between unsaved objects make it much easier to build big graphs that only make sense to be saved together. Support for SQLite3 and MySQL 4.1.1+ has been added. Rails has also added support for expressions such as 45.kilobytes + 2.3.megabytes and 45.minutes + 2.hours.