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Posted to common-dev@hadoop.apache.org by "Doug Cutting (JIRA)" <ji...@apache.org> on 2008/03/26 19:33:26 UTC
[jira] Created: (HADOOP-3097) mapred.map.tasks and
mapred.reduce.tasks should be determined automatically by default
mapred.map.tasks and mapred.reduce.tasks should be determined automatically by default
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Key: HADOOP-3097
URL: https://issues.apache.org/jira/browse/HADOOP-3097
Project: Hadoop Core
Issue Type: New Feature
Components: mapred
Reporter: Doug Cutting
The default values for mapred.map.tasks and mapred.reduce.tasks should be empty or -1, signalling that the framework should use an dynamically-determined default. An appropriate default is perhaps the number of map and reduce slots in the cluster, since FileInputFormat interprets mapred.map.tasks as a minimum.
This would remove a common area of misconfiguration.
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[jira] Commented: (HADOOP-3097) mapred.map.tasks and
mapred.reduce.tasks should be determined automatically by default
Posted by "Owen O'Malley (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3097?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12587902#action_12587902 ]
Owen O'Malley commented on HADOOP-3097:
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+1 for using the cluster defaults for this. I might suggest using #map slots * 2.0 and # reduce slots * 0.99 since those seem to be a little better defaults that 1.0 for both maps and reduces.
> mapred.map.tasks and mapred.reduce.tasks should be determined automatically by default
> --------------------------------------------------------------------------------------
>
> Key: HADOOP-3097
> URL: https://issues.apache.org/jira/browse/HADOOP-3097
> Project: Hadoop Core
> Issue Type: New Feature
> Components: mapred
> Reporter: Doug Cutting
>
> The default values for mapred.map.tasks and mapred.reduce.tasks should be empty or -1, signalling that the framework should use an dynamically-determined default. An appropriate default is perhaps the number of map and reduce slots in the cluster, since FileInputFormat interprets mapred.map.tasks as a minimum.
> This would remove a common area of misconfiguration.
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