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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Range Slice Issue
Date Tue, 03 May 2011 17:37:17 GMT
Do you still see this behavior if you disable dynamic snitch?

On Tue, May 3, 2011 at 12:31 PM, Serediuk, Adam
<Adam.Serediuk@serialssolutions.com> wrote:
> We appear to have encountered an issue with cassandra 0.7.5 after upgrading
> from 0.7.2. While doing a batch read using a get_range_slice against the
> ranges an individual node is master for we are able to reproduce
> consistently that the last two nodes in the ring, regardless of the ring
> size (we have a 60 node production cluster and a 12 node test cluster)
> perform this read over the network using replicas of executing locally.
> Every other node in the ring successfully reads locally.
> To be sure there were no data consistency issues we performed a nodetool
> repair against both of these nodes and the issue persists. We also tried
> truncating the column family and repopulating, but the issue remains.
> This seems to be related to CASSANDRA-2286 in 0.7.4. We always want to read
> data locally if it is available there. We
> use Cassandra.Client.describe_ring() to figure out which machine in the
> ring is master for which TokenRange. I then compare the master for
> each TokenRange against the localhost to find out which token ranges
> are owned by the local machine (remote reads are too slow for this type
> of batch processing). Once I know which TokenRanges are on
> each machine locally I get evenly sized splits using
> Cassandra.Client.describe_splits().
>
> Adam
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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