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From: Jonathan Ellis <jbellis@gmail.com>
Date: Tue, 3 May 2011 12:37:17 -0500
Message-ID: <BANLkTik3Lv8xBqTK+MpgE5kAn2ftEw9bNA@mail.gmail.com>
Subject: Re: Range Slice Issue
To: user@cassandra.apache.org
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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 upgradi=
ng
> 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=A0CASSANDRA-2286 in 0.7.4. We always want to =
read
> data locally if it is available there. We
> use=A0Cassandra.Client.describe_ring() to figure out which machine in the
> ring=A0is master for which TokenRange. I then compare the master for
> each=A0TokenRange against the localhost=A0to find out which token ranges
> are=A0owned by the local machine (remote reads are too slow for this type
> of=A0batch processing). Once I know which TokenRanges are on
> each=A0machine=A0locally I get evenly sized splits using
> Cassandra.Client.describe_splits().
>
> Adam
>


--=20
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com