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From Bill de hOra <b...@dehora.net>
Subject Re: Incr/Decr Counters in Cassandra
Date Wed, 04 Nov 2009 22:09:24 GMT
incr/decr for counters maybe doesn't fit with EC (as you might need a 
global lock for some use cases ), but plus/minus are slightly different 
as they're commutative and don't require a total ordering.

Bill

Michael Greene wrote:
> This has come up before at http://markmail.org/thread/w3mrh4h64xpf3vuj
> and http://markmail.org/message/vnmsuddlrhaziq7g
> I am in favor of adding eventually-consistent atomic operations such
> as this, but I'm not sure how one would implement it.  Some sort of
> UUID + bloomfilter for the individual atomic operations?  I tend to
> think "retrieve and increment" as requested by Jon is at odds with
> eventual consistency, but maybe I'm wrong.
> 
> Michael
> 
> On Wed, Nov 4, 2009 at 3:51 PM, Bill de hOra <bill@dehora.net> wrote:
>>
>> Chris Goffinet wrote:
>>> Hey,
>>>
>>> At Digg we've been thinking about counters in Cassandra. In a lot of our
>>> use cases we need this type of support from a distributed storage system.
>>> Anyone else out there who has such needs as well? Zookeeper actually has
>>> such support and we might use that if we can't get the support in Cassandra.
>> I tend to need a generalization on incr/decr which is plus/minus (eg for
>> quota management). Having these in Cassandra would be great.
>>
>> Bill
>>


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