incubator-cassandra-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Sandeep Tata <>
Subject Re: [jira] Commented: (CASSANDRA-48) test-and-set
Date Fri, 03 Apr 2009 16:10:47 GMT
Well, the test and set failed could have failed because of a new value
replacing the old one since this client read it.
Jun is talking about re-reading to get this new value and retrying the

On Fri, Apr 3, 2009 at 9:08 AM, Jonathan Ellis (JIRA) <> wrote:
>    [
> Jonathan Ellis commented on CASSANDRA-48:
> -----------------------------------------
> The client should not do that.  It knows the old version (or it couldn't be doing test-and-set)
and it knows the new version and it knows that not all replicas were written but some were.
 Doing a read cannot possibly tell it anything it doesn't already know.
>> test-and-set
>> ------------
>>                 Key: CASSANDRA-48
>>                 URL:
>>             Project: Cassandra
>>          Issue Type: Improvement
>>            Reporter: Jonathan Ellis
>> Atomic test-and-set insert operation would be nice: "set value to X but only if the
current value is still Y."  This allows a sort of optimistic consistency: perform a GET,
then perform test-and-set with the value of that GET as Y.
>> I do not think that this requires strong consistency to be useful.
> --
> This message is automatically generated by JIRA.
> -
> You can reply to this email to add a comment to the issue online.

View raw message