On 1, countandra.org. On 2, the issue is a little more deep (we have investigated this at countandra). To approach it a little more comprehensively, the issue has more to do with events rather than counts (at least in IMO).
A similar issue is about averages... countandra does sums and counts quite easily; thanks to Cassandra's counter columns. However Averages are a little more challenging in the eventually consistent world. Average = Sum/Count. However which Sum and which Count? You can have a Sum and Count from different times and divide the two and you might get a division by zero or 0/sum. We are investigating the use of Interval Time Clocks (ITCs) as the mechanism for co-ordinating these times. Incidentally the use of the ITC can be used to produce globally consistent snapshots across nodes of Cassandra. Regards Milind On Fri, May 25, 2012 at 11:55 AM, Furcy Pin <fu...@qunb.com> wrote: > Hi all, > > I am currently investigating the possibilities of Cassandra for my company, > I have played around with Hector and Cassandra for a month now, and I have > a few questions to ask (in a separate mail for each topic). > > So here are my first questions: > > 1) > I found the CounterColumns to be a very powerful feature. I heard that it > was more or less the implementation of Rainbird described > by Twitter a year ago, and was supposed to go open source one day (Cf > http://techcrunch.com/2011/02/04/twitter-rainbird/ ) Is it true? > > 2) > More seriously: do you think Cassandra-2833 will be done one day? What > about Cassandra-1132? > I think having CounterColumns being able to manage double and min/max > operation would be quite useful features (at least for my company). > > Thanks for your time, > > Furcy > > PS: if anyone happens to live in Paris (I know :-( ), I would be glad to > talk about Cassandra around a beer. >
