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From "Stu Hood" <>
Subject RE: Help with MapReduce
Date Sun, 18 Apr 2010 21:37:19 GMT
ColumnFamilyInputFormat no longer uses the fat client API, and instead uses Thrift. There are
still some significant problems with the fat client, so it shouldn't be used without a good
understanding of those problems.

If you still want to use it, check out contrib/bmt_example, but I'd recommend that you use
thrift for now.

-----Original Message-----
From: "Joost Ouwerkerk" <>
Sent: Sunday, April 18, 2010 2:59pm
Subject: Help with MapReduce

I'm a Cassandra noob trying to validate Cassandra as a viable alternative to
HBase (which we've been using for over a year) for our application.  So far,
I've had no success getting Cassandra working with MapReduce.

My first step is inserting data into Cassandra.  I've created a MapRed job
based using the fat client API.  I'm using the fat client (StorageProxy)
because that's what ColumnFamilyInputFormat uses and I want to use the same
API for both read and write jobs.

When I call StorageProxy.mutate(), nothing happens.  The job completes as if
it had done something, but in fact nothing has changed in the cluster.  When
I call StorageProxy.mutateBlocking(), I get an IOException complaining that
there is no connection to the cluster.  I've concluded with the debugger
that StorageService is not connecting to the cluster, even though I've
specified the correct seed and ListenAddress (I've using the exact same
storage-conf.xml as the nodes in the cluster).

I'm sure I'm missing something obvious in the configuration or my setup, but
since I'm new to Cassandra, I can't see what it is.

Any help appreciated,

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