Add an example of a secondary sort

• Key: HADOOP-4545
• Type: Improvement
• Status: Closed
• Resolution: Fixed
• Priority: Major
• Assignee: Owen O'Malley
• Reporter: Owen O'Malley
• Fix Version/s: 0.20.0

Description

We should have an example of using secondary sort.

Comments

[Owen O'Malley]

Here is an example.

[Chris Douglas]

Looks good. A unit test using this example would also be helpful; there aren't many tests that use the grouping comparator.

[Owen O'Malley]

This patch:
1. Updates the example to the new map/reduce api
2. Adds a unit test case.

[Chris Douglas]

+1

[Owen O'Malley]

I just committed this.

[Hudson]

Integrated in Hadoop-trunk #698 (See http://hudson.zones.apache.org/hudson/job/Hadoop-trunk/698/)

[Rares Vernica]

In the example, is there a typo in the hashCode function of IntPair?

    public int hashCode() {
      return first * 157 + second;
                     ^^^
                     127?
    }

Here is the .java file: http://svn.apache.org/viewvc/hadoop/core/trunk/src/examples/org/apache/hadoop/examples/SecondarySort.java