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https://issues.apache.org/jira/browse/CASSANDRA-5062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13591781#comment-13591781
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Jonathan Ellis commented on CASSANDRA-5062:
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I think you missed this part:
bq. Instead of replicas checking raw timeuuid order for propose/promise, they
will require that a new ballot be larger in the time component than an accepted
ballot or mostRecentCommitted. (We do still want to use a timeuuid value though
instead of a raw timestamp to guarantee uniqueness across proposals.)
and this:
bq. Rejecting "newer" proposals w/ equal time components slows us down (we
return false and client has to try again w/ a newer ballot) but does not
compromise correctness.
(So we do not "rely" on monotonically increasing timestamps; we reject
coordinators until they propose an acceptable one.)
> Support CAS
> -----------
>
> Key: CASSANDRA-5062
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5062
> Project: Cassandra
> Issue Type: New Feature
> Components: API, Core
> Reporter: Jonathan Ellis
> Fix For: 2.0
>
> Attachments: half-baked commit 1.jpg, half-baked commit 2.jpg,
> half-baked commit 3.jpg
>
>
> "Strong" consistency is not enough to prevent race conditions. The classic
> example is user account creation: we want to ensure usernames are unique, so
> we only want to signal account creation success if nobody else has created
> the account yet. But naive read-then-write allows clients to race and both
> think they have a green light to create.
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