My db is Cassandra (datastax enterprise => linux). Since it doesn't support group-by, aggregate and etc. for reporting, according to its fundamentals, it's not a good decision to use Cassandra, downright. I googled about this deficit and found some results as this, and this and also this one.
But I really became confused! Hive uses additional tables, individually. Solr is better for full-text searching and like that. And Spark...it's useful for analysis, but, I didn't understand if it uses Hadoop eventually, or not.
I will have many reports, which needs indexing and grouping, at least. But I don't want to use additional tables which will impose overhead. And also, I'm .Net (and not Java) developer, and my application is besed on .Net Framework, too.