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From Chris Burroughs <chris.burrou...@gmail.com>
Subject Re: Question: ConsistencyLevel.ONE with multiple datacenters
Date Thu, 06 Feb 2014 13:31:29 GMT
I think the scenario you outlined is correct.  The DES handles multiple 
DCs poorly and the LOCAL_ONE hammer is the best bet.

On 01/31/2014 12:40 PM, Paulo Ricardo Motta Gomes wrote:
> Hey,
>
> When adding a new data center to our production C* datacenter using the
> procedure described in [1], some of our application requests were returning
> null/empty values. Rebuild was not complete in the new datacenter, so my
> guess is that some requests were being directed to the brand new datacenter
> which still didn't have the data.
>
> Our Hector client was connected only to the original nodes, with
> autoDiscoverHosts=false and we use ConsistencyLevel.ONE for reads. The
> keyspace schema was already configured to use both data centers.
>
> My question is: is it possible that the dynamic snitch is choosing the
> nodes in the new (empty) datacenter when CL=ONE? In this case, it's
> mandatory to use CL=LOCAL_ONE during bootstrap/rebuild of a new datacenter,
> otherwise empty data might be returned, correct?
>
> Cheers,
>
> [1]
> http://www.datastax.com/documentation/cassandra/1.2/webhelp/cassandra/operations/ops_add_dc_to_cluster_t.html
>


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