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From Sandeep Tata <sandeep.t...@gmail.com>
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
"transaction"

On Fri, Apr 3, 2009 at 9:08 AM, Jonathan Ellis (JIRA) <jira@apache.org> wrote:
>
>    [ https://issues.apache.org/jira/browse/CASSANDRA-48?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12695470#action_12695470
]
>
> 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: https://issues.apache.org/jira/browse/CASSANDRA-48
>>             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.
>
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>

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