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https://issues.apache.org/jira/browse/CASSANDRA-5544?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13667978#comment-13667978
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Cyril Scetbon commented on CASSANDRA-5544:
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[~alexliu68] I did some tests with more than 64k row and had only one mapper
for the whole cluster. Even if we have less than 64k rows, why don't we have at
least one mapper per node (in my case replication_factor=1) to work on rows
using data locality. Vnodes are enabled on my cluster, can there be a relation
with this option ?
> 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: 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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