As for the atomic increment, I take the answer is 'no, there is no atomic increment, I have to pull the value to the client and send an update with the new value'.
Saying "atomic increment" is probably confusing. 
You cannot have Counters, the thing most people would think about when you say "increment", in a collection type.

You can update the values in a map server side. 

If you can provide a concrete example of what you want to do it may be easier. 

Cheers
 
-----------------
Aaron Morton
Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 6/08/2013, at 10:05 PM, Andy Twigg <andy.twigg@gmail.com> wrote:

Counters can be atomically incremented (http://wiki.apache.org/cassandra/Counters). Pick a UUID for the counter, and use that: c=map.get(k); c.incr()


On 6 August 2013 11:01, Jan Algermissen <jan.algermissen@nordsc.com> wrote:

On 06.08.2013, at 11:36, Andy Twigg <andy.twigg@gmail.com> wrote:

> Store pointers to counters as map values?

Sorry, but this fits into nothing I know about C* so far - can you explain?

Jan




--
Dr Andy Twigg
Junior Research Fellow, St Johns College, Oxford
Room 351, Department of Computer Science
http://www.cs.ox.ac.uk/people/andy.twigg/
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