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From "Paulo Ricardo Motta Gomes (JIRA)" <j...@apache.org>
Subject [jira] [Created] (CASSANDRA-6436) AbstractColumnFamilyInputFormat does not use start and end tokens configured via ConfigHelper.setInputRange()
Date Tue, 03 Dec 2013 14:31:37 GMT
Paulo Ricardo Motta Gomes created CASSANDRA-6436:
----------------------------------------------------

             Summary: AbstractColumnFamilyInputFormat does not use start and end tokens configured
via ConfigHelper.setInputRange()
                 Key: CASSANDRA-6436
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6436
             Project: Cassandra
          Issue Type: Bug
          Components: Hadoop
            Reporter: Paulo Ricardo Motta Gomes
             Fix For: 1.2.6


ConfigHelper allows to set a token input range via the setInputRange(conf, startToken, endToken)
call (ConfigHelper:254).

We used this feature to limit a hadoop job range to a single Cassandra node's range, or even
to single row key, mostly for testing purposes. 

This worked before the fix for CASSANDRA-5536 (https://github.com/apache/cassandra/commit/aaf18bd08af50bbaae0954d78d5e6cbb684aded9),
but after this ColumnFamilyInputFormat never uses the value of KeyRange.start_token when defining
the input splits (AbstractColumnFamilyInputFormat:142-160), but only KeyRange.start_key, which
needs an order preserving partitioner to work.

I propose the attached fix in order to allow defining Cassandra token ranges for a given Hadoop
job even when using a non-order preserving partitioner.

Example use of ConfigHelper.setInputRange(conf, startToken, endToken) to limit the range to
a single Cassandra Key with RandomPartitioner: 

IPartitioner part = ConfigHelper.getInputPartitioner(job.getConfiguration());
Token token = part.getToken(ByteBufferUtil.bytes("Cassandra Key"));
BigInteger endToken = (BigInteger) new BigIntegerConverter().convert(BigInteger.class, part.getTokenFactory().toString(token));
BigInteger startToken = endToken.subtract(new BigInteger("1"));
ConfigHelper.setInputRange(job.getConfiguration(), startToken.toString(), endToken.toString());



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