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Getting empty output file after running hadoop code

New Contributor

This is the below output iam getting after running my code i have attached my file of the code

kindly revert back

as iam new to hadoop and have been working on this error for the last couple of days

17/05/16 14:17:01 INFO mapred.LocalJobRunner: reduce > reduce

17/05/16 14:17:01 INFO mapred.Task: Task 'attempt_local1523217778_0001_r_000000_0' done.

17/05/16 14:17:01 INFO mapred.LocalJobRunner: Finishing task: attempt_local1523217778_0001_r_000000_0

17/05/16 14:17:01 INFO mapred.LocalJobRunner: reduce task executor complete.

17/05/16 14:17:01 INFO mapreduce.Job: Job job_local1523217778_0001 running in uber mode : false

17/05/16 14:17:01 INFO mapreduce.Job: map 0% reduce 100%

17/05/16 14:17:01 INFO mapreduce.Job: Job job_local1523217778_0001 completed successfully

17/05/16 14:17:01 INFO mapreduce.Job: Counters: 29

File System Counters

FILE: Number of bytes read=53030675

FILE: Number of bytes written=53719810

FILE: Number of read operations=0

FILE: Number of large read operations=0

FILE: Number of write operations=0

HDFS: Number of bytes read=0

HDFS: Number of bytes written=0

HDFS: Number of read operations=6

HDFS: Number of large read operations=0

HDFS: Number of write operations=3

Map-Reduce Framework

Combine input records=0

Combine output records=0

Reduce input groups=0

Reduce shuffle bytes=0

Reduce input records=0

Reduce output records=0

Spilled Records=0

Shuffled Maps =0

Failed Shuffles=0

Merged Map outputs=0

GC time elapsed (ms)=0

Total committed heap usage (bytes)=123797504

Shuffle Errors







File Output Format Counters

Bytes Written=0

My code

config class

import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import; import; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.GenericOptionsParser; public class IPLTConfig { public static void main(String... args) throws Throwable { Configuration conf = new Configuration(); Job job = new Job(conf, "IPLT"); String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs(); job.setCombinerClass(IPLTReducer.class); job.setReducerClass(IPLTReducer.class); job.setMapperClass(IPLTMapper.class); job.setJarByClass(IPLTConfig.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); FileInputFormat.addInputPath(job, new Path(otherArgs[0])); FileOutputFormat.setOutputPath(job, new Path(otherArgs[1])); System.exit(job.waitForCompletion(true) ? 0 : 1); } }

import; import java.util.StringTokenizer; import; import; import; import org.apache.hadoop.mapreduce.Mapper; public class IPLTMapper extends Mapper<LongWritable, Text, Text, IntWritable> { private final IntWritable one = new IntWritable(1); private Text word = new Text(); @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { StringTokenizer iter = new StringTokenizer(value.toString()); while (iter.hasMoreTokens()) { word.set(iter.nextToken()); context.write(word, one); } } }

Reducer class

import; import java.util.Iterator; import; import; import org.apache.hadoop.mapreduce.Reducer; public class IPLTReducer extends Reducer<Text, IntWritable, Text, IntWritable> { private IntWritable result = new IntWritable(); @Override protected void reduce(Text word, Iterable<IntWritable> intOne, Context context) throws IOException, InterruptedException { int sum = 0; Iterator<IntWritable> iter = intOne.iterator(); while (iter.hasNext()) sum +=; result.set(sum); context.write(word, result); } }


Expert Contributor

Your code is fine, I copy-pasted it to a project and it works.

Could you please provide the followings:

  • Hadoop version you're using
  • How you called the MapReduce job
  • Complete logs of the job
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