[MAPREDUCE-5059] Job overview shows average merge time larger than for any reduce attempt

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.1.0-beta, 0.23.8
• Component/s: jobhistoryserver, webapps
• Hadoop Flags: Reviewed
• Assignee: Omkar Vinit Joshi
• Reporter: Jason Darrell Lowe
• Created: 12/Mar/13 19:09
• Updated: 27/Aug/13 22:22
• Resolved: 29/Jul/13 05:43

Description

When looking at a job overview page on the history server, the Average Merge Time is often reported with a value that is far larger than the Elapsed Merge Time shown for any reduce task attempt. The job overview page calculates the merge time as the time delta between the sort finishing and the job launching while the attempts page calculates it as the time delta between the sort finishing and the shuffle finishing.