Appropriate database for web analytics?
I think you are looking for DBs that are designed for analytics.
May be you should check these solutions:.
some data storage solutions specific to realtime analytics

Druid
Spark
Cassandra
Hbase
hypertable
accumulo

reference:

http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis
http://relistan.com/cassandra-vs-mongo/