The reason was that I set the mapred-site.xml to use the new api. Thanks,
On Thu, Jan 27, 2011 at 5:04 PM, Chase Bradford
<chase.bradf...@gmail.com> wrote:
> That's very puzzling, because I don't see any reason for the new API
> to get activated. I'm pretty sure that's what's happening though,
> based on this section of the exception's call stack:
>
> 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)
>
>
>
> On Thu, Jan 27, 2011 at 8:50 AM, Pedro Costa <psdc1...@gmail.com> wrote:
>> [code]
>>
>> package org.apache.hadoop.examples;
>>
>> import java.io.IOException;
>> import java.math.BigDecimal;
>> import java.util.Iterator;
>>
>> import org.apache.hadoop.conf.Configured;
>> import org.apache.hadoop.fs.FileSystem;
>> import org.apache.hadoop.fs.Path;
>> import org.apache.hadoop.io.BooleanWritable;
>> import org.apache.hadoop.io.LongWritable;
>> import org.apache.hadoop.io.SequenceFile;
>> import org.apache.hadoop.io.Writable;
>> import org.apache.hadoop.io.WritableComparable;
>> import org.apache.hadoop.io.SequenceFile.CompressionType;
>> import org.apache.hadoop.mapred.FileInputFormat;
>> import org.apache.hadoop.mapred.FileOutputFormat;
>> import org.apache.hadoop.mapred.JobClient;
>> import org.apache.hadoop.mapred.JobConf;
>> import org.apache.hadoop.mapred.MapReduceBase;
>> import org.apache.hadoop.mapred.Mapper;
>> import org.apache.hadoop.mapred.OutputCollector;
>> import org.apache.hadoop.mapred.Reducer;
>> import org.apache.hadoop.mapred.Reporter;
>> import org.apache.hadoop.mapred.SequenceFileInputFormat;
>> import org.apache.hadoop.mapred.SequenceFileOutputFormat;
>> import org.apache.hadoop.util.Tool;
>> import org.apache.hadoop.util.ToolRunner;
>>
>>
>> public class PiEstimator extends Configured implements Tool {
>> /** tmp directory for input/output */
>> static private final Path TMP_DIR = new
>> Path(PiEstimator.class.getSimpleName() + "_TMP_3_141592654");
>>
>>
>> /**
>> * Mapper class for Pi estimation.
>> * Generate points in a unit square
>> * and then count points inside/outside of the inscribed circle of
>> the square.
>> */
>> public static class PiMapper extends MapReduceBase
>> implements Mapper<LongWritable, LongWritable, BooleanWritable,
>> LongWritable> {
>>
>> /** Map method.
>> * @param offset samples starting from the (offset+1)th
>> sample.
>> * @param size the number of samples for this map
>> * @param out output {ture->numInside, false->numOutside}
>> * @param reporter
>> */
>> public void map(LongWritable offset,
>> LongWritable size,
>> OutputCollector<BooleanWritable,
>> LongWritable> out,
>> Reporter reporter) throws IOException {
>>
>> final HaltonSequence haltonsequence = new
>> HaltonSequence(offset.get());
>> long numInside = 0L;
>> long numOutside = 0L;
>>
>> for(long i = 0; i < size.get(); ) {
>> //generate points in a unit square
>> final double[] point =
>> haltonsequence.nextPoint();
>>
>> //count points inside/outside of the
>> inscribed circle of the square
>> final double x = point[0] - 0.5;
>> final double y = point[1] - 0.5;
>> if (x*x + y*y > 0.25) {
>> numOutside++;
>> } else {
>> numInside++;
>> }
>>
>> //report status
>> i++;
>> if (i % 1000 == 0) {
>> reporter.setStatus("Generated " + i +
>> " samples.");
>> }
>> }
>>
>> //output map results
>> out.collect(new BooleanWritable(true), new
>> LongWritable(numInside));
>> out.collect(new BooleanWritable(false), new
>> LongWritable(numOutside));
>> }
>> }
>>
>>
>>
>> /**
>> * Run a map/reduce job for estimating Pi.
>> *
>> * @return the estimated value of Pi
>> */
>> public static BigDecimal estimate(int numMaps, long numPoints,
>> JobConf jobConf)
>> throws IOException {
>> //setup job conf
>> jobConf.setJobName(PiEstimator.class.getSimpleName());
>>
>> jobConf.setInputFormat(SequenceFileInputFormat.class);
>>
>> jobConf.setOutputKeyClass(BooleanWritable.class);
>> jobConf.setOutputValueClass(LongWritable.class);
>> //
>> jobConf.setMapOutputKeyClass(BooleanWritable.class);
>> //
>> jobConf.setMapOutputValueClass(LongWritable.class);
>> jobConf.setOutputFormat(SequenceFileOutputFormat.class);
>>
>> jobConf.setMapperClass(PiMapper.class);
>> jobConf.setNumMapTasks(numMaps);
>>
>> jobConf.setReducerClass(PiReducer.class);
>> jobConf.setNumReduceTasks(1);
>>
>> // turn off speculative execution, because DFS doesn't handle
>> // multiple writers to the same file.
>> jobConf.setSpeculativeExecution(false);
>>
>> //setup input/output directories
>> final Path inDir = new Path(TMP_DIR, "in");
>> final Path outDir = new Path(TMP_DIR, "out");
>> FileInputFormat.setInputPaths(jobConf, inDir);
>> FileOutputFormat.setOutputPath(jobConf, outDir);
>>
>> final FileSystem fs = FileSystem.get(jobConf);
>> if (fs.exists(TMP_DIR)) {
>> throw new IOException("Tmp directory " +
>> fs.makeQualified(TMP_DIR)
>> + " already exists. Please remove it
>> first.");
>> }
>> if (!fs.mkdirs(inDir)) {
>> throw new IOException("Cannot create input directory
>> " + inDir);
>> }
>>
>> try {
>> //generate an input file for each map task
>> for(int i=0; i < numMaps; ++i) {
>> final Path file = new Path(inDir, "part"+i);
>> final LongWritable offset = new
>> LongWritable(i * numPoints);
>> final LongWritable size = new
>> LongWritable(numPoints);
>> final SequenceFile.Writer writer =
>> SequenceFile.createWriter(
>> fs, jobConf, file,
>> LongWritable.class,
>> LongWritable.class, CompressionType.NONE);
>> try {
>> writer.append(offset, size);
>> } finally {
>> writer.close();
>> }
>> System.out.println("Wrote input for Map #"+i);
>> }
>>
>> //start a map/reduce job
>> System.out.println("Starting Job");
>> final long startTime = System.currentTimeMillis();
>> JobClient.runJob(jobConf);
>> final double duration = (System.currentTimeMillis() -
>> startTime)/1000.0;
>> System.out.println("Job Finished in " + duration + "
>> seconds");
>>
>> //read outputs
>> Path inFile = new Path(outDir, "reduce-out");
>> LongWritable numInside = new LongWritable();
>> LongWritable numOutside = new LongWritable();
>> SequenceFile.Reader reader = new
>> SequenceFile.Reader(fs, inFile, jobConf);
>> try {
>> reader.next(numInside, numOutside);
>> } finally {
>> reader.close();
>> }
>>
>> //compute estimated value
>> return BigDecimal.valueOf(4).setScale(20)
>> .multiply(BigDecimal.valueOf(numInside.get()))
>> .divide(BigDecimal.valueOf(numMaps))
>> .divide(BigDecimal.valueOf(numPoints));
>> } finally {
>> fs.delete(TMP_DIR, true);
>> }
>> }
>>
>> /**
>> * Parse arguments and then runs a map/reduce job.
>> * Print output in standard out.
>> *
>> * @return a non-zero if there is an error. Otherwise, return 0.
>> */
>> public int run(String[] args) throws Exception {
>> if (args.length != 2) {
>> System.err.println("Usage: "+getClass().getName()+"
>> <nMaps> <nSamples>");
>> ToolRunner.printGenericCommandUsage(System.err);
>> return -1;
>> }
>>
>> final int nMaps = Integer.parseInt(args[0]);
>> final long nSamples = Long.parseLong(args[1]);
>>
>> System.out.println("Number of Maps = " + nMaps);
>> System.out.println("Samples per Map = " + nSamples);
>>
>> final JobConf jobConf = new JobConf(getConf(), getClass());
>> System.out.println("Estimated value of Pi is "
>> + estimate(nMaps, nSamples, jobConf));
>> return 0;
>> }
>> }
>>
>> [/code]
>>
>>
>>
>> On Thu, Jan 27, 2011 at 4:44 PM, Chase Bradford
>> <chase.bradf...@gmail.com> wrote:
>>> That should be fine, but mapreduce.Mapper.map has this signature:
>>>
>>> map(K key, V value, Context)
>>>
>>> Your PiEstimator map signature doesn't match, so it's not overriding
>>> the proper function and is never getting called by the framework.
>>>
>>> Could you paste your complete PiMapper class definition and the series
>>> of calls you make to setup your job? That would make debugging the
>>> problem much easier.
>>>
>>> Chase
>>>
>>>
>>> On Thu, Jan 27, 2011 at 8:29 AM, Pedro Costa <psdc1...@gmail.com> wrote:
>>>> Yes, that's the one that's being used ( o.a.h.mapreduce.Mapper ). This
>>>> is not the right one to use?
>>>>
>>>>
>>>>
>>>> On Thu, Jan 27, 2011 at 3:40 PM, Chase Bradford
>>>> <chase.bradf...@gmail.com> wrote:
>>>>> 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
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Pedro
>>>>
>>>
>>>
>>>
>>> --
>>> Chase Bradford
>>>
>>>
>>> “If in physics there's something you don't understand, you can always
>>> hide behind the uncharted depths of nature. But if your program
>>> doesn't work, there is no obstinate nature. If it doesn't work, you've
>>> messed up.”
>>>
>>> - Edsger Dijkstra
>>>
>>
>>
>>
>> --
>> Pedro
>>
>
>
>
> --
> Chase Bradford
>
>
> “If in physics there's something you don't understand, you can always
> hide behind the uncharted depths of nature. But if your program
> doesn't work, there is no obstinate nature. If it doesn't work, you've
> messed up.”
>
> - Edsger Dijkstra
>
--
Pedro
