|Mondrian cell-caching architecture, including pluggable external cache.|
Luc Boudreau has been leading this effort, has just checked in the first revision of the new mondrian.rolap.agg.SegmentCache interface, and has written a blog post describing how it will work. (Note: This SPI is likely to change before we release it.)
Pluggable caching will be in Mondrian release 3.3, probably Q2 or Q3 this year.In the community edition will be the SPI and a default implementation that uses JVM memory. Of course the community will be able to contribute alternative implementations. In the enterprise edition of Mondrian 3.3, there will be scalable, highly manageable implementation based on something like Terracotta BigMemory, ehCache or JBoss Infinispan.
In future releases, you can expect to see further work in the area. Maybe alternative implementations of the caching SPI, and certainly tuning of Mondrian's caching and evaluation strategies, as we apply Mondrian to some of the biggest data sets out there.