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From Adrian Mocanu <>
Subject RE: trident simplest aggregator into cassandra
Date Mon, 03 Feb 2014 22:18:34 GMT
I installed the latest version of Cassandra 4 weeks ago: version 2


From: Huang, Roger []
Sent: February-03-14 5:14 PM
Subject: RE: trident simplest aggregator into cassandra

What version of Cassandra are you using?

From: Adrian Mocanu []
Sent: Monday, February 03, 2014 4:09 PM
Subject: trident simplest aggregator into cassandra

I'm using Trident to perform some aggregations and store the results into cassandra.

I've looked at IBackingMap and specifically at some tutorials on trident site and I've tried
using CassandraState which I found online in some repository. After creating what I thought
were column family and keys corresponding to the code I still cannot figure out how to run
the sample topology and not crash due to some Cassandra schema error (InvalidRequestException(why:Invalid
cell for CQL3 table state. The CQL3 column component (over) does not correspond to a defined
CQL3 column).

Here is the sample code I use:

  val cassandraStateFactory:StateFactory = chat.CassandraState.transactional("")

    val spout = new FixedBatchSpout(new Fields("sentence"), 3,
      new Values("the cow jumped over the moon"),
      new Values("the man went to the store and bought some candy"),
      new Values("four score and seven years ago"),
      new Values("how many apples can you eat"))

    val wordCounts :TridentState= tridentBuilder.newStream("spout1", spout)
      .each(new Fields("sentence"), new Split(), new Fields("word"))
      .groupBy(new Fields("word"))
      .persistentAggregate(cassandraStateFactory, new Count(), new Fields("count"))

    val cluster = new LocalCluster();
    val config = new Config();
    cluster.submitTopology("test", config,;

What is the schema needed to run this example (it also uses CassandraState)?


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