title: Is there a multi-key key-value store?
body: <p>Is there a specialized store for storing tuples i.e. t=(clicks, impressions, ctr) hashed on multiple values - let's say pageId, categoryId, userId, sessionId et cetera.</p>
  
  <p>I know I could do this using MySQL, MongoDb et cetera. But I am more looking for some specialized and mabye even embedded (in Java) store. It does not need to offer a complex query language or transactions like RDMBS. But atomicity and durability would be a pro. ;)</p>
  
  <p>I figure this could also be of use for DWH-type applications storing aggregate data in multiple dimensions but I have not found any such product.</p>