Count data written in last 15 min to Cassandra

Question

In Cassandra each written column has a timestamp which can be accessed using the getClock() method (once pooled from the DB).

I would like to know how many columns got written in the last X minutes (let's say 15 minutes) to Cassandra. I looked at the secondary index pattern but could not find it usable for my needs.

Is there a way of doing that (I don't mind which client - CQL, CLI, Hector etc').

Answer 1

Cassandra exposes a lot of metrics about itself, including request counts and latencies as JMX beans. Run JConsole against one of your Cassandra nodes and find org.apache.cassandra.metrics.ColumnFamily. Below it in the tree there will be nodes for each table, within each keyspace. Pick the WriteLatency MBean and look at it's attributes; the FifteenMinuteRate is the number of write requests per second on average over the last 15 minutes. Count is the total number of write requests.