Are you sure the function signature for you Mapper's map matches the super
class, and that you specified your Map class in the job setup? It sounds a bit
like the base o.a.h.mapreduce.Mapper map implementation is being used instead.
On Jan 27, 2011, at 2:36 AM, Pedro Costa <psdc1...@gmail.com> wrote:
> The map output class are well defined:
> keyClass: class org.apache.hadoop.io.BooleanWritable - valClass: class
> org.apache.hadoop.io.LongWritable
>
> but executing the pi example, the values that map function passes is:
> keyClass: class org.apache.hadoop.io.LongWritable - valClass: class
> org.apache.hadoop.io.Text
>
>
> I looked at the PiEstimator.class.PiMapper#map function, and the
> output collector seems ok.
>
> [code]
> public void map(LongWritable offset,
> LongWritable size,
> OutputCollector<BooleanWritable, LongWritable> out,
> Reporter reporter) throws IOException {
> (...)
> out.collect(new BooleanWritable(true), new LongWritable(numInside));
> out.collect(new BooleanWritable(false), new LongWritable(numOutside));
> }
> [/code]
>
> I'm really confused, right now. How can this be happening?
>
>
> On Thu, Jan 27, 2011 at 10:19 AM, Pedro Costa <psdc1...@gmail.com> wrote:
>> Thanks Nicholas, but it didn't worked.
>>
>> Can I do a remote debugging on hadoop examples? I really like to put a
>> breakpoint in the Pi class.
>>
>> Thanks,
>>
>> On Wed, Jan 26, 2011 at 6:46 PM, Tsz Wo (Nicholas), Sze
>> <s29752-hadoopu...@yahoo.com> wrote:
>>> Okay, I got it now. You were talking about your programs but not the
>>> PiEstimator example came from Hadoop. Then, you have to set
>>> "mapred.output.key.class" and "mapred.output.value.class" as Srihari
>>> mentioned. Below are the APIs.
>>>
>>> //new API
>>> final Job job = ...
>>> job.setMapOutputKeyClass(BooleanWritable.class);
>>> job.setMapOutputValueClass(LongWritable.class);
>>>
>>> //old API
>>> final JobConf jobconf = ...
>>> jobconf.setOutputKeyClass(BooleanWritable.class);
>>> jobconf.setOutputValueClass(LongWritable.class);
>>>
>>> Nicholas
>>>
>>> ________________________________
>>> From: Srihari Anantha Padmanabhan <sriha...@yahoo-inc.com>
>>> To: "mapreduce-user@hadoop.apache.org" <mapreduce-user@hadoop.apache.org>
>>> Sent: Wed, January 26, 2011 10:36:09 AM
>>> Subject: Re: PiEstimator error - Type mismatch in key from map
>>>
>>> I am using Hadoop 0.20.2. I just wrote my own map-reduce program based on
>>> the map-reduce tutorial at
>>> http://hadoop.apache.org/common/docs/r0.20.2/mapred_tutorial.html
>>>
>>> On Jan 26, 2011, at 10:27 AM, Pedro Costa wrote:
>>>
>>>> Hadoop 20.1
>>>>
>>>> On Wed, Jan 26, 2011 at 6:26 PM, Tsz Wo (Nicholas), Sze
>>>> <s29752-hadoopu...@yahoo.com> wrote:
>>>>> Hi Srihari,
>>>>>
>>>>> Same questions to you: Which version of Hadoop are you using? And where
>>>>> did
>>>>> you get the examples? I guess you were able to reproduce it. I suspect
>>>>> the
>>>>> examples and the Hadoop are in different versions.
>>>>>
>>>>> Nicholas
>>>>>
>>>>>
>>>>> ________________________________
>>>>> From: Srihari Anantha Padmanabhan <sriha...@yahoo-inc.com>
>>>>> To: "mapreduce-user@hadoop.apache.org" <mapreduce-user@hadoop.apache.org>
>>>>> Sent: Wed, January 26, 2011 10:15:08 AM
>>>>> Subject: Re: PiEstimator error - Type mismatch in key from map
>>>>>
>>>>> I got a similar error before in one of my projects. I had to set the
>>>>> values
>>>>> for "mapred.output.key.class" and "mapred.output.value.class".
>>>>> That resolved the issue for me.
>>>>> Srihari
>>>>> On Jan 26, 2011, at 10:09 AM, Pedro Costa wrote:
>>>>>
>>>>> Yes, I can reproduce it deterministically. But, I also did some
>>>>> changes to the Hadoop MR code. Most definitely this is the reason. I'm
>>>>> looking throughly through the code.
>>>>>
>>>>> I'll say something after I find the problem.
>>>>>
>>>>> I was just wondering if this error has happened to someone before.
>>>>> Maybe I could get a hint and try to see what's my problem easily.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> On Wed, Jan 26, 2011 at 6:02 PM, Tsz Wo (Nicholas), Sze
>>>>> <s29752-hadoopu...@yahoo.com> wrote:
>>>>>
>>>>> 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 <psdc1...@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
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Pedro
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Pedro
>>>
>>>
>>
>>
>>
>> --
>> Pedro
>>
>
>
>
> --
> Pedro
