[MAPREDUCE-3901] lazy load JobHistory Task and TaskAttempt details

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.0
• Fix Version/s: 0.23.2
• Component/s: jobhistoryserver, mrv2
• Target Version/s: 0.23.2
• Hadoop Flags: Reviewed
• Release Note: Modified JobHistory records in YARN to lazily load job and task reports so as to improve UI response times.
• Assignee: Siddharth Seth
• Reporter: Siddharth Seth
• Created: 23/Feb/12 03:02
• Updated: 04/Mar/12 00:29
• Resolved: 28/Feb/12 00:35

Description

The job history UI and MRClientProtocol calls routed via JobHistory are very slow for large jobs. Some of this time is spent parsing the history file. A good chunk is spent pre-creating lots of objects which may never be used. Those can be create when required - bringing down the load times of job history pages and getJobReport etc calls to approximately the history file parse time.