Overview | Package | Class | Use | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## org.apache.hadoop.examples
Class RandomWriter

    java.lang.Object
      org.apache.hadoop.conf.Configured
          org.apache.hadoop.examples.RandomWriter

All Implemented Interfaces:
  Configurable, Tool

    public class RandomWriter

extends Configured
implements Tool

This program uses map/reduce to just run a distributed job where there is no interaction between the tasks and each task write a large unsorted random binary sequence file of BytesWritable. In order for this program to generate data for terasort with 10-byte keys and 90-byte values, have the following config:

     <?xml version="1.0"?>
     <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
     <configuration>
       <property>
         <name>test.randomwrite.min_key</name>
         <value>10</value>
       </property>
       <property>
         <name>test.randomwrite.max_key</name>
         <value>10</value>
       </property>
       <property>
         <name>test.randomwrite.min_value</name>
         <value>90</value>
       </property>
       <property>
         <name>test.randomwrite.max_value</name>
         <value>90</value>
       </property>
       <property>
         <name>test.randomwrite.total_bytes</name>
         <value>1099511627776</value>
       </property>
     </configuration>

Equivalently, `RandomWriter` also supports all the above options and ones supported by `GenericOptionsParser` via the command-line.

Constructor Summary
`RandomWriter()`

Method Summary
`static void` | `main(String[] args)`
`int` | `run(String[] args)` This is the main routine for launching a distributed random write job.

Methods inherited from class org.apache.hadoop.conf.Configured
`getConf, setConf`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Methods inherited from interface org.apache.hadoop.conf.Configurable
`getConf, setConf`

Constructor Detail

### RandomWriter

    public RandomWriter()

Method Detail

### run

    public int run(String[] args)
            throws Exception

  This is the main routine for launching a distributed random write job. It runs 10 maps/node and each node writes 1 gig of data to a DFS file. The reduce doesn't do anything.

  Specified by:
    `run` in interface `Tool`
  Parameters:
    `args` - command specific arguments.
  Returns:
    exit code.
  Throws:
    `IOException`
    `Exception`

### main

    public static void main(String[] args)
                     throws Exception

  Throws:
    `Exception`

Overview | Package | Class | Use | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

Copyright © 2009 The Apache Software Foundation