[MAPREDUCE-3490] RMContainerAllocator counts failed maps towards Reduce ramp up

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.23.0
• Fix Version/s: 0.23.1
• Component/s: mr-am, mrv2
• Target Version/s: 0.23.1
• Hadoop Flags: Reviewed
• Release Note: Fixed MapReduce AM to count failed maps also towards Reduce ramp up.
• Assignee: Sharad Agarwal
• Reporter: Siddharth Seth
• Created: 01/Dec/11 01:17
• Updated: 05/Mar/12 02:49
• Resolved: 04/Jan/12 17:12

Description

The RMContainerAllocator does not differentiate between failed and successful maps while calculating whether reduce tasks are ready to launch. Failed tasks are also counted towards total completed tasks.
Example. 4 failed maps, 10 total maps. Map%complete = 4/14 * 100 instead of being 0.