Hi, After some research I have decided that Spark (SQL) would be ideal for building an OLAP engine. My goal is to push aggregated data (to Cassandra or other low-latency data storage) and then be able to project the results on a web page (web service). New data will be added (aggregated) once a day, only. On the other hand, the web service must be able to run some fixed(?) queries (either on Spark or Spark SQL) at anytime and plot the results with D3.js. Note that I can already achieve similar speeds while in REPL mode by caching the data. Therefore, I believe that my problem must be re-phrased as follows: "How can I automatically cache the data once a day and make them available on a web service that is capable of running any Spark or Spark (SQL) statement in order to plot the results with D3.js?"
Note that I have already some experience in Spark (+Spark SQL) as well as D3.js but not at all with OLAP engines (at least in their traditional form). Any ideas or suggestions? *// Adamantios*