org.apache.hadoop.mapred.lib
Class InputSampler.IntervalSampler<K,V>

java.lang.Object
  org.apache.hadoop.mapred.lib.InputSampler.IntervalSampler<K,V>

All Implemented Interfaces:

InputSampler.Sampler<K,V>

Enclosing class:

InputSampler<K,V>

public static class InputSampler.IntervalSampler<K,V>
extends Object
implements InputSampler.Sampler<K,V>

Sample from s splits at regular intervals. Useful for sorted data.

Constructor Summary

InputSampler.IntervalSampler(double freq)
Create a new IntervalSampler sampling all splits.

InputSampler.IntervalSampler(double freq, int maxSplitsSampled)
Create a new IntervalSampler.

Method Summary

K[]	getSample(InputFormat<K,V> inf, JobConf job) For each split sampled, emit when the ratio of the number of records retained to the total record count is less than the specified frequency.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

InputSampler.IntervalSampler

public InputSampler.IntervalSampler(double freq)

Create a new IntervalSampler sampling all splits.

Parameters:

freq - The frequency with which records will be emitted.

InputSampler.IntervalSampler

public InputSampler.IntervalSampler(double freq,
                                    int maxSplitsSampled)

Create a new IntervalSampler.

Parameters:

freq - The frequency with which records will be emitted.

maxSplitsSampled - The maximum number of splits to examine.

See Also:

getSample(org.apache.hadoop.mapred.InputFormat, org.apache.hadoop.mapred.JobConf)

Method Detail

getSample

public K[] getSample(InputFormat<K,V> inf,
                     JobConf job)
              throws IOException

For each split sampled, emit when the ratio of the number of records retained to the total record count is less than the specified frequency.

Specified by:

getSample in interface InputSampler.Sampler<K,V>

Throws:

IOException