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Jonathan Ellis commented on CASSANDRA-5062: ------------------------------------------- bq. it feels to me that having one paxos state per row is more "natural" All right. Done and pushed. bq. I think that we may want to TTL the Paxos state Hmm, not sure where to fit this in. We store gcgs in the schema, but system tables are not user-modifiable (and even if they were, this one is node-local). I guess we could add a global config setting, which doesn't thrill me. bq. the current patch can get in a state where for a row no CAS operation on that row can be done at all (they will all UAE) until the user does a manual repair, because if less than a quorum of replica have received the last MRC commit message I must be missing something, because that's by design -- this sounds exactly like what we discussed to preserve correctness. "On result of the prepare, we would wait for a quorum of people agreeing on the last MRC (i.e. a quorum has learn the last value) before allowing to proceed with our own value." > 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. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira