Druid OLAP type

Hi -

Just out of curiosity what OLAP type does Druid fall in to (MOLAP, ROLAP or HOLAP)? One of my colleague was classifying Druid as ROLAP, but I wasn’t sure if it falls under ROLAP as we have column oriented datastore for every dimension and we can access the data for slicing very quickly and with indexes for filtering data, it sounds closer to MOLAP.


Druid support small table/large table joins but does not currently support large table/large table joins. Really Druid doesn’t have ideas of pre-computation built into it, so it is closer to MOLAP in that sense.

If it doesn’t require any pre-computation then it should be considered closer to ROLAP as well.

It’s columnar storage and not Relational so it’s closer to MOLAP as well.

Plus it has real time and historical serving nodes so it’s should be considered HOLAP as well.

I think HOLAP is a better term to describe it.