title: Cassandra schema advice needed
body: <p>I'm designing a Cassandra schema for a browser event collection system, and I was hoping to sanity check my approach. The system collects user events in the browser, like mouse movements, clicks, etc. The events are stored and processed to create heat maps of user activity on a web page. I've chosen Cassandra for persistence, since my use case is more write  heavy than ready heavy: every 50 milliseconds, an ajax call dumps the aggregated events to my server, and into the database. I'm using node.js for the server, and the JSON events look something like this on the server: </p>
  
  <pre><code>{ uuid: dsf86ag487hadf97hadf97, type: 'MOVE', time: 12335234345, pageX: 334, pageY:566, .... }
  </code></pre>
  
  <p>As you can see each user has a unique uuid, associated with each of their events, generated on the browser, stored in a cookie. My read case will be some map-reduce job. Each top-level domain will be a keyspace, and I was planning using the uuid as my partition key. The main table will be the events table, where each row will be one event, using a composite primary key, consisting of the browser-generated uuid and a cassandra-generated timeuuid. The primary key must have a timeuuid component, since two events may have the same timestamp on certain browsers. The data types for event will be strings, ints, timestamps. The total data for a partition should not exceed a few hundred megabytes. So...Is this sane? What questions should I be asking myself? I recognize that this use case has many analogs in sensor data collection, etc, so please point me to existing examples. Thanks in advance.       </p>