IEfficiently maintaining history data on line together with current data is difficult. This paper discusses one promising approach, the temporally partitioned store. The current store contains current data and possibly some history data, whil the history store holds the rest of the data. The two stores can utilize different storage formats, and even different storage media, depending on the individual data characteristics. We discuss various issues on the temporally partitioned store, investigate several formats for the history store, and evaluate their performance on a set of sample queries.