[
https://issues.apache.org/jira/browse/CASSANDRA-5544?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13668633#comment-13668633
]
Alex Liu commented on CASSANDRA-5544:
-------------------------------------
CassandraColumnInputFormat define the split size, so we don't want Pig to
override it by combining splits. We can always tune the split size to tune the
performance. Next step, we can open up a little bit so that Pig user can
specify split size configuration.
Vnode hadoop performance generally decreases, we can do the split combination
at Cassandra side to improve the performance, which could be another ticket.
> 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.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>
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
