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From Ted Yu <yuzhih...@gmail.com>
Subject Re: HBase MR - key/value mismatch
Date Thu, 05 Sep 2013 14:34:23 GMT
public class SentimentCalculationHBaseReducer extends

        TableReducer<Text, Text, ImmutableBytesWritable> {

The first type parameter for reducer should be ImmutableBytesWritable

Cheers


On Wed, Sep 4, 2013 at 11:16 PM, Omkar Joshi <Omkar.Joshi@lntinfotech.com>wrote:

> I'm trying to execute a MR code over stand-alone HBase(0.94.11). I had
> read the HBase api and modified my MR code to read data and getting
> exceptions in the Reduce phase.
>
> The exception I get is :
>
> 13/09/05 16:16:17 INFO mapred.JobClient:  map 0% reduce 0%
>
> 13/09/05 16:23:31 INFO mapred.JobClient: Task Id :
> attempt_201309051437_0005_m_000000_0, Status : FAILED
>
> java.io.IOException: wrong key class: class
> org.apache.hadoop.hbase.io.ImmutableBytesWritable is not class
> org.apache.hadoop.io.Text
>
>         at org.apache.hadoop.mapred.IFile$Writer.append(IFile.java:164)
>
>         at
> org.apache.hadoop.mapred.Task$CombineOutputCollector.collect(Task.java:1168)
>
>         at
> org.apache.hadoop.mapred.Task$NewCombinerRunner$OutputConverter.write(Task.java:1492)
>
>         at
> org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
>
>         at
> com.hbase.mapreduce.SentimentCalculationHBaseReducer.reduce(SentimentCalculationHBaseReducer.java:199)
>
>         at
> com.hbase.mapreduce.SentimentCalculationHBaseReducer.reduce(SentimentCalculationHBaseReducer.java:1)
>
>         at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:176)
>
>         at
> org.apache.hadoop.mapred.Task$NewCombinerRunner.combine(Task.java:1513)
>
>         at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.sortAndSpill(MapTask.java:1436)
>
>         at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.flush(MapTask.java:1298)
>
>         at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.close(MapTask.java:699)
>
>         at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:766)
>
>         at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
>
>         at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
>
>         at java.security.AccessController.doPrivileged(Native Method)
>
>         at javax.security.auth.Subject.doAs(Subject.java:415)
>
>         at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1149)
>
>         at org.apache.hadoop.mapred.Child.main(Child.java:249)
>
>
>
> Providing the partial(excluding the business logic) codes
>
>
> Mapper:
>
>
> public class SentimentCalculationHBaseMapper extends TableMapper<Text,
> Text> {
>
>
>
> private Text sentenseOriginal = new Text();
>
> private Text sentenseParsed = new Text();
>
>
>
> @Override
>
>     protected void map(
>
>             ImmutableBytesWritable key,
>
>             Result value,
>
>             org.apache.hadoop.mapreduce.Mapper<ImmutableBytesWritable,
> Result, Text, Text>.Context context)
>
>             throws IOException, InterruptedException {
>
> context.write(this.sentenseOriginal, this.sentenseParsed);
>
> }
>
> }
>
> Reducer :
>
>
> public class SentimentCalculationHBaseReducer extends
>
>         TableReducer<Text, Text, ImmutableBytesWritable> {
>
>
>
> @Override
>
>     protected void reduce(
>
>             Text key,
>
>             java.lang.Iterable<Text> values,
>
>             org.apache.hadoop.mapreduce.Reducer<Text, Text,
> ImmutableBytesWritable, org.apache.hadoop.io.Writable>.Context context)
>
>             throws IOException, InterruptedException {
>
>
>
> Double mdblSentimentOverall = 0.0;
>
>
>
>
>
> String d3 = key + "@12321@" + s11.replaceFirst(":::", "")
>
>                     + "@12321@" + mstpositiveWords + "@12321@"
>
>                     + mstnegativeWords + "@12321@" + mstneutralWords;
>
>
>
>             System.out.println("d3 : " + d3 + " , mdblSentimentOverall : "
>
>                     + mdblSentimentOverall);
>
>
>
>             Put put = new Put(d3.getBytes());
>
>
>
>             put.add(Bytes.toBytes("word_attributes"),
>
>                     Bytes.toBytes("mdblSentimentOverall"),
>
>                     Bytes.toBytes(mdblSentimentOverall));
>
>
>
>             System.out.println("Context is " + context);
>
>
>
>             context.write(new ImmutableBytesWritable(d3.getBytes()), put);
>
> }
>
> }
>
> SentimentCalculatorHBase - the Tool/main class :
> package com.hbase.mapreduce;
>
> import java.util.Calendar;
>
> import org.apache.hadoop.conf.Configuration;
> import org.apache.hadoop.conf.Configured;
> import org.apache.hadoop.hbase.client.Put;
> import org.apache.hadoop.hbase.client.Scan;
> import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
> import org.apache.hadoop.hbase.mapreduce.TableInputFormat;
> import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
> import org.apache.hadoop.hbase.mapreduce.TableOutputFormat;
> import org.apache.hadoop.io.Text;
> import org.apache.hadoop.mapreduce.Job;
> import org.apache.hadoop.util.Tool;
> import org.apache.hadoop.util.ToolRunner;
>
> public class SentimentCalculatorHBase extends Configured implements Tool {
>
>     /**
>      * @param args
>      * @throws Exception
>      */
>     public static void main(String[] args) throws Exception {
>         // TODO Auto-generated method stub
>         SentimentCalculatorHBase sentimentCalculatorHBase = new
> SentimentCalculatorHBase();
>         ToolRunner.run(sentimentCalculatorHBase, args);
>     }
>
>     @Override
>     public int run(String[] arg0) throws Exception {
>         // TODO Auto-generated method stub
>
>
>         System.out
>                 .println("***********************Configuration
> started***********************");
>         Configuration configuration = getConf();
>         System.out.println("Conf: " + configuration);
>
>
>         Job sentiCalcJob = new Job(configuration, "HBase
> SentimentCalculation");
>
>         sentiCalcJob.setJarByClass(SentimentCalculatorHBase.class);
>         sentiCalcJob.setMapperClass(SentimentCalculationHBaseMapper.class);
>
> sentiCalcJob.setCombinerClass(SentimentCalculationHBaseReducer.class);
>
> sentiCalcJob.setReducerClass(SentimentCalculationHBaseReducer.class);
>
>
>         sentiCalcJob.setInputFormatClass(TableInputFormat.class);
>         sentiCalcJob.setOutputFormatClass(TableOutputFormat.class);
>
>         /* Start : Added out of exasperation! */
>         sentiCalcJob.setOutputKeyClass(ImmutableBytesWritable.class);
>         sentiCalcJob.setOutputValueClass(Put.class);
>         /* End : Added out of exasperation! */
>
>         Scan twitterdataUserScan = new Scan();
>         twitterdataUserScan.setCaching(500);
>
>         twitterdataUserScan.addColumn("word_attributes".getBytes(),
>                 "TwitterText".getBytes());
>
>         TableMapReduceUtil.initTableMapperJob("twitterdata_user",
>                 twitterdataUserScan, SentimentCalculationHBaseMapper.class,
>                 Text.class, Text.class, sentiCalcJob);
>
>         TableMapReduceUtil.initTableReducerJob("sentiment_output",
>                 SentimentCalculationHBaseReducer.class, sentiCalcJob);
>
>         Calendar beforeJob = Calendar.getInstance();
>         System.out.println("Job Time started---------------- "
>                 + beforeJob.getTime());
>         boolean check = sentiCalcJob.waitForCompletion(true);
>         if (check == true) {
>             System.out
>                     .println("*******************Job completed-
> SentimentCalculation********************");
>         }
>         Calendar afterJob = Calendar.getInstance();
>         System.out
>                 .println("Job Time ended
> SentimentCalculation---------------- "
>                         + afterJob.getTime());
>         return 0;
>     }
> }
>
>
>
> Regards,
> Omkar Joshi
>
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