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Posted to user@cassandra.apache.org by Sal Fuentes <fu...@gmail.com> on 2011/08/25 01:50:35 UTC

Atomic or Non-Atomic Counters

The design document that is referenced on the Cassandra wiki page (
http://wiki.apache.org/cassandra/Counters) describes the Counters in
Cassandra as non-atomic (
https://issues.apache.org/jira/secure/attachment/12459754/Partitionedcountersdesigndoc.pdf).
However, the DataStax post on counters (
http://www.datastax.com/dev/blog/whats-new-in-cassandra-0-8-part-2-counters)
suggests that they are atomic. My impression is that the design document is
outdated (Nov2010). Can someone confirm or deny that these Counters are
atomic?



-- 
Salvador Fuentes Jr.

Re: Atomic or Non-Atomic Counters

Posted by Jonathan Ellis <jb...@gmail.com>.

They are atomic in the sense that if you increment from N to M,
readers will never see any intermediate values, just N or M itself.

On Wed, Aug 24, 2011 at 6:50 PM, Sal Fuentes <fu...@gmail.com> wrote:
> The design document that is referenced on the Cassandra wiki page
> (http://wiki.apache.org/cassandra/Counters) describes the Counters in
> Cassandra as non-atomic
> (https://issues.apache.org/jira/secure/attachment/12459754/Partitionedcountersdesigndoc.pdf).
> However, the DataStax post on counters
> (http://www.datastax.com/dev/blog/whats-new-in-cassandra-0-8-part-2-counters)
> suggests that they are atomic. My impression is that the design document is
> outdated (Nov2010). Can someone confirm or deny that these Counters are
> atomic?
>
>
> --
> Salvador Fuentes Jr.
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com