无论怎样，我们的数据库访问会越来越快，选择的机会很多。
http://www.theserverside.com/home/thread.jsp?thread_id=18719&article_count=4
不过我的应用大多要求实时的数据，很少会用到这样的 Cache.
Very often people can choose improve Cache on DB side directly if they just need to speed up query. Few of my customers' systems allocate Giga bytes RAM for DB buffer and super fast network plus some middle tier cache.
Middle tier cache is more versatile in general, I mean in general.