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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (CASSANDRA-3172) Add CL.ANY_QUORUM to support quorum requests with cross datacenter failover
Date Sat, 10 Sep 2011 23:01:09 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-3172?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jonathan Ellis resolved CASSANDRA-3172.
---------------------------------------

    Resolution: Won't Fix

ANY_QUORUM is far from likely to be (entirely) consistent since as soon as enough local nodes
recover, reads will prefer that instead.

More fundamentally, you're overcomplicating things.  If you're okay with reads occasionally
not being 100% (locally) consistent, then use CL.ONE (or TWO if you want to guarantee redundancy
on writes).  If you're not, then stick with LOCAL_QUORUM.

> Add CL.ANY_QUORUM to support quorum requests with cross datacenter failover
> ---------------------------------------------------------------------------
>
>                 Key: CASSANDRA-3172
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-3172
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: API, Core
>            Reporter: Mark Guzman
>            Priority: Minor
>
> Currently we provide CL.LOCAL_QUORUM and CL.EACH_QUORUM. CL.ANY_QUORUM would operate
like CL.LOCAL_QUORUM if a local quorum is possible, if it is not the coordinator would use
its knowledge to select the "fastest/closest" node in another datacenter to attempt another
LOCAL_QUORUM in. This would allow for simple reliable cross datacenter failover without putting
the intelligence in the client. The client is intrinsically at a disadvantage since it doesn't
have a current full picture of the rings.

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