Dave

Tyler's answer already covers CFs etc..

We are using Cassandra to store user profile data for exactly the sort of use case you describe. We don't yet store _all_ the data in Cassandra; currently we are focusing on the stuff we need available for real-time access. We use Hadoop to analyse the profiles from within Cassandra.

Dave

On 23 February 2011 23:21, Dave Viner <daveviner@gmail.com> wrote:
Hi all,

I'm wondering if anyone has used cassandra as a datastore for a user-profile service.  I'm thinking of applications like behavioral targeting, where there are lots & lots of users (10s to 100s of millions), and lots & lots of data about them intermixed in, say, weblogs (probably TBs worth).  The idea would be to use Cassandra as a datastore for distributed parallel processing of the TBs of files (say on hadoop).  Then the resulting user-profiles would be query-able quickly.

Anyone know of that sort of application of Cassandra?  I'm trying to puzzle out just what the column family might look like.  Seems like a mix of time-oriented information (user x visits site y at time z), location information (user x appeared from ip x.y.z.a which is geo-location 31.20309, 120.10923), and derived information (because user x visited site y 15 times within a 10 day window, user x must be interested in buying a car).

I don't have specifics as yet... just some general thoughts.  But this feels like a Cassandra type problem.  (User profile can have lots of columns per user, but the exact columns might differ from user to user... very scalable, etc)

Thanks
Dave Viner