I don't understand much about this apache/java data streaming ecosystem (ETL, Kafka, Cassandra, they're all buzzword bingo to me and i don't know what it all means), but maybe someone here can translate this to simpler application programmer terms?<p>I read the overview, and I'm not sure yet, but is this like an in-memory database that runs inside your process? Like, sqlite without disk persistence, or Erlang ETS, but then columnar?<p>I can't completely tell from the overview whether it's about the data format or the querying capability. A columnar ETS alternative would be splendid indeed!