java.io.IOException: Type mismatch in value from map: expected org.apache.hadoop.hbase.client.Put, recieved org.apache.hadoop.io.BytesWritable

[praveenesh kumar]

Hi all,

I am trying to write a MR code to load a HBase table.

I have a mapper that emits (null,put object) and I am using
TableMapReduceUtil.initTableReducerJob() to write it into a HBase table.

Following is my code snippet

public class MYHBaseLoader extends
Mapper<NullWritable,BytesWritable,NullWritable,Put> {

     protected void map (LongWritable key, BytesWritable value, Context
context) throws IOException, InterruptedException {

      /****----- Some processing here.. Create put object and pushing it
into Put object).
        context.write(null, put);// Pushing the put object.

    }

    public static void main (String args[]) throws IOException,
ClassNotFoundException, InterruptedException{
        Configuration conf = new Configuration();
        Job job = new Job(conf);
        job.setJarByClass(MYHBaseLoader.class);
        job.setMapperClass(MYHBaseLoader.class);

TableMapReduceUtil.initTableReducerJob(MY_IMPORT_TABLE_NAME,IdentityTableReducer.class,job);
        job.setMapOutputKeyClass(NullWritable.class);
        job.setMapOutputValueClass(Put.class);
        job.setInputFormatClass(SequenceFileInputFormat.class);
        //job.setNumReduceTasks(0);

        FileInputFormat.setInputPaths(job, new Path("test"));
        Path outputPath = new Path("test_output");
        FileOutputFormat.setOutputPath(job,outputPath);

        //outputPath.getFileSystem(conf).delete(outputPath, true);

        job.waitForCompletion(true);
        System.out.println("Done");
    }


I am getting the following error while running. Any help/guidance:


java.io.IOException: Type mismatch in value from map: expected
org.apache.hadoop.hbase.client.Put, recieved
org.apache.hadoop.io.BytesWritable
    at
org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1023)
    at
org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:689)
    at
org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
    at org.apache.hadoop.mapreduce.Mapper.map(Mapper.java:124)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:763)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:363)
    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:396)
    at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1232)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)


Regards
Praveenesh