Note: See the corresponding lecture notes about MapReduce. This page has cookbook recipes.
Kill a job
On delenn, first list the active jobs:
Find yours, then kill it:
mapred job -kill <job-id>
Find out which file is being processed by map
Map over files recursively
Want to process all files in a directory and subdirectories? Use this technique:
Only map over files that match a certain regex
Create a class that implements
PathFilter. The class below can be configured to use any regular expression:
Use it like so:
It might be good to combine this technique with the ‘recursive’ technique above.