Hadoop: Number of reducer is not equal to what I have set in program

Question

I have set mapred.tasktracker.reduce.tasks.maximum to 10 in mapred-site.xml, and I also write jobConf.setNumReduceTasks(5) in my job.

Everythin

Answer 1

Running it in eclipse seems to use the local job runner. It only supports 0 or 1 reducers. If you try to set it to use more than one reducer, it ignores it and just uses one anyway.