The 'employees with age = 35' scenario is exactly what they are useful for.
There's a quick section in the pycassa documentation that might be useful: http://pycassa.github.com/pycassa/tutorial.html#indexes On Mon, Nov 29, 2010 at 11:41 PM, Narendra Sharma <narendra.sha...@gmail.com > wrote: > > > On Mon, Nov 29, 2010 at 9:32 PM, Jonathan Ellis <jbel...@gmail.com> wrote: > >> On Mon, Nov 29, 2010 at 11:26 PM, Narendra Sharma >> <narendra.sha...@gmail.com> wrote: >> > Thanks Jonathan. >> > >> > Couple of more questions: >> > 1. Is there any technical limit on the number of secondary indexes that >> can >> > be created? >> >> Just as with traditional databases, the more indexes there are the >> slower writes to that CF will be. >> >> > 2. Is it possible to execute join queries spanning multiple secondary >> > indexes? >> >> What do secondary indexes have to do with joins? >> > > For eg if I want to get all employees that are male and have age = 35 > years. How can secondary indexes be useful in such scenario? > >> >> -- >> Jonathan Ellis >> Project Chair, Apache Cassandra >> co-founder of Riptano, the source for professional Cassandra support >> http://riptano.com >> > >
