maxConcurrentMapTask & maxConcurrentReduceTask per job ------------------------------------------------------
Key: MAPREDUCE-1859 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1859 Project: Hadoop Map/Reduce Issue Type: New Feature Components: job submission Affects Versions: 0.20.2 Reporter: Johannes Zillmann It would be valuable if one could specify the max number of map/reduce slots which should be used for a given job. An example would be an map-reduce job importing from a database where you don't want 50 map tasks querying one db at a time but also you don't want to shrink the overall map task count. Also this is probably already possible through Fair/Capacity-Scheduler or an own Extension i think it would be a good addition for the default TaskScheduler since this seems to be more then a rare used feature. This would have the benefit in situations where you don't have control/ownership over the cluster as well. And its more job-centric whereas the existing scheduler extensions seems to be more job-type-centric. Implementing this feature should be relatively straightforward. Adding something like jobConf.setMaxConcurrentMapTask(int) and respecting this configuration in JobQueueTaskScheduler. Not sure if this feature would be harmonical with the existing Fair/Capacity-Schedulers. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.