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From "Tsz Wo \(Nicholas\), Sze" <s29752-hadoopu...@yahoo.com>
Subject Re: PiEstimator error - Type mismatch in key from map
Date Wed, 26 Jan 2011 18:02:20 GMT
Hi Pedro,
This is interesting.  Which version of Hadoop are you using?  And where did you 
get the example class files?  Also, are you able to reproduce it 
deterministically?
Nicholas




________________________________
From: Pedro Costa <psdc1978@gmail.com>
To: mapreduce-user@hadoop.apache.org
Sent: Wed, January 26, 2011 5:47:01 AM
Subject: PiEstimator error - Type mismatch in key from map

Hi,

I run the PI example of hadoop, and I've got the following error:

[code]
java.io.IOException: Type mismatch in key from map: expected
org.apache.hadoop.io.BooleanWritable, recieved
org.apache.hadoop.io.LongWritable
    at 
org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:885)
    at 
org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:551)
    at 
org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:81)

    at org.apache.hadoop.mapreduce.Mapper.map(Mapper.java:124)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:637)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.Child.main(Child.java:190)
[/code]

I've look at the map function of the class "PiEstimator.class" and it seems ok.

[code]
public void map(LongWritable offset,
        LongWritable size,
        OutputCollector<BooleanWritable, LongWritable> out,
        Reporter reporter) throws IOException {}
[/code]


What's wrong with this examples?

Thanks,
-- 
Pedro

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