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https://issues.apache.org/jira/browse/CASSANDRA-5544?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13669054#comment-13669054
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Shamim Ahmed commented on CASSANDRA-5544:
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Alex, thank you very much for your quick response. 
However, i am afraid that above patch will not solve the problem i described 
"we got more than 100 maps but 2 of them (always two maps) got very large Map 
input records and runs more than hours - point 4" - this behavior is 
unexpected. This means Map input records is not evenly through cluster, most of 
the maps getting  Map input records = 10000 but only two of them getting more 
than millions.
Certainly i will do some test through thrift api as you described. 
One more things, would you kindly allows user to define PIG_INPUT_SPLIT_SIZE 
through cassandra store URL as "STORE updated INTO 
'cassandra://KEYSPACE/CF?allow_deletes=true&PIG_INPUT_SPLIT_SIZE=xxxxxx' USING 
CassandraStorage()" instead of system environment.
                
> Hadoop jobs assigns only one mapper in task 
> --------------------------------------------
>
>                 Key: CASSANDRA-5544
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5544
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Hadoop
>    Affects Versions: 1.2.1
>         Environment: Red hat linux 5.4, Hadoop 1.0.3, pig 0.11.1
>            Reporter: Shamim Ahmed
>            Assignee: Alex Liu
>         Attachments: 5544-1.txt, 5544.txt, Screen Shot 2013-05-26 at 4.49.48 
> PM.png
>
>
> We have got very strange beheviour of hadoop cluster after upgrading 
> Cassandra from 1.1.5 to Cassandra 1.2.1. We have 5 nodes cluster of 
> Cassandra, where three of them are hodoop slaves. Now when we are submitting 
> job through Pig script, only one map assigns in task running on one of the 
> hadoop slaves regardless of 
> volume of data (already tried with more than million rows).
> Configure of pig as follows:
> export PIG_HOME=/oracle/pig-0.10.0
> export PIG_CONF_DIR=${HADOOP_HOME}/conf
> export PIG_INITIAL_ADDRESS=192.168.157.103
> export PIG_RPC_PORT=9160
> export PIG_PARTITIONER=org.apache.cassandra.dht.Murmur3Partitioner
> Also we have these following properties in hadoop:
>  <property>
>  <name>mapred.tasktracker.map.tasks.maximum</name>
>  <value>10</value>
>  </property>
>  <property>
>  <name>mapred.map.tasks</name>
>  <value>4</value>
>  </property>

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