mondrian的缓存文档翻译

1. 简介
mondrian的设计优势在于，在实现OLAP查询前你不必做任何处理以生成特殊的数据结构。正因为如此，很多人觉得mondrian是“实时OLAP”(在不断变化的数据库上运行多维数据查询)的不二选择。
One of the strengths of mondrian's design is that you don't need to do any processing to populate special data structures before you start running OLAP queries. More than a few people have observed that this makes mondrian an excellent choice for 'real-time OLAP' -- running multi-dimensional queries on a database which is constantly changing.
mondrian的缓存带来了一些问题。通常情况下缓存是好的，因为它保证了对指定数据，mondrian只要去DBMS里做一次查询。但当数据库的数据变化的时候，缓存的数据就过期了。
The problem is that mondrian's cache gets in the way. Usually the cache is a great help, because it ensures that mondrian only goes to the DBMS once for a given piece of data, but the cache becomes out of date if the underlying database is changing.
一系列的缓存控制的API解决了以上问题.在哥解释API前，让咱们理解下mondrian是如何缓存数据的
This is solved with a set of APIs for cache control. Before I explain the API, let's understand how mondrian caches data.
2、mondrian的缓存是如何工作的？