If you're just indexing on a single column value and the values have low cardinality in, say, the 10's - I'd have a wide row for each cardinal value that contained the set of keys for rows that contained that value. For higher levels of cardinality or if you're indexing on multiple columns, there are tradeoffs for secondary indexes versus CF inverted indexes that are based on atomicity of updates, complexity of queries, and whether you need to get results in sorted order. Secondary indexes are usually the best starting point since they're easy to set up and use, versus CF inverted indexes, where you'll need to manage all that yourself. Some of the client libraries make it easier to build CF inverted indexes, Hector is going to soon have some capabilities for JPA users leveraging the new composite column types to do this. I wrote up a blog post a while back talking about indexing approaches at http://www.anuff.com/2011/02/indexing-in-cassandra.html that you might find useful, although it sounds like you're already familiar with the concepts
Ed On Fri, Apr 8, 2011 at 7:53 AM, Adi <adi.pan...@gmail.com> wrote: > I am trying to decide whether to use secondary indexes or use an inverted > index column family for a use case. Is there any suggested ballpark range > for low cardinality for which secondary indexes are suitable. > Meaning at what range should using a secondary index be ruled in or out: > cardinality of tens, hundreds, thousands,millions? > I am not looking for any tested numbers a general suggestion/best practice > recommendation will suffice. > > Thanks. > > -Adi > >
