What are the merits of using CouchDB vs Hadoop to store/analyze web app log data?
I can only speak for CouchDB, but the main benefits of using a document database to store things like these are;
- They are schema less so that you can alter the schema of your log entries and still perform queries on the various editions of the schema you might have.
- The map/reduce algorithm is a very powerful way to do grouping queries.
- REST interface makes it technology agnostic in terms of consuming the data.
- Scaling is horizontal and "infinite".