The previous chapters have been exclusively concerned with Websphere eXtreme Scale and its use as a cache and persistent data store. By using the partitioning and replication functions, which we'll look at in the next few chapters, we can build a production-worthy application with persistent, reliable, and durable data storage, without ever touching a disk. However, there are a few key features that data grids lack.
There are three compelling reasons to integrate with a database backend. First, reporting tools do not have good data grid integration. Using CrystalReports and other reporting tools, don't work with data grids right now. Loading data from a data grid into a data warehouse with existing tools isn't possible either.
The second reason we want to use a database with a data grid is when we have an extremely large data set. A data grid stores data in memory. Though much cheaper than in the past, system memory is still much more expensive than a typical...