[MAPREDUCE-6020] Too many threads blocking on the global JobTracker lock from getJobCounters, optimize getJobCounters to release global JobTracker lock before access the per job counter in JobInProgress

• Type: Improvement
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.23.10
• Labels: BB2015-05-TBR
• Assignee: Zhihai Xu
• Reporter: Zhihai Xu
• Created: 31/Jul/14 22:37
• Updated: 08/May/15 07:23

Description

Too many threads blocking on the global JobTracker lock from getJobCounters, optimize getJobCounters to release global JobTracker lock before access the per job counter in JobInProgress. It may be a lot of JobClients to call getJobCounters in JobTracker at the same time, Current code will lock the JobTracker to block all the threads to get counter from JobInProgress. It is better to unlock the JobTracker when get counter from JobInProgress(job.getCounters(counters)). So all the theads can run parallel when access its own job counter.

Issue Links

• is related to: YARN-2376 Too many threads blocking on the global JobTracker lock from getJobCounters, optimize getJobCounters to release global JobTracker lock before access the per job counter in JobInProgress