[YARN-4047] ClientRMService getApplications has high scheduler lock contention

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.6.1, 2.8.0, 2.7.2, 3.0.0-alpha1
• Component/s: resourcemanager
• Labels: 2.6.1-candidate
• Target Version/s: 2.7.2
• Hadoop Flags: Reviewed
• Assignee: Jason Darrell Lowe
• Reporter: Jason Darrell Lowe
• Created: 11/Aug/15 19:51
• Updated: 06/Jan/17 07:37
• Resolved: 13/Aug/15 23:16

Description

The getApplications call can be particuarly expensive because the code can call checkAccess on every application being tracked by the RM. checkAccess will often call scheduler.checkAccess which will grab the big scheduler lock. This can cause a lot of contention with the scheduler thread which is busy trying to process node heartbeats, app allocation requests, etc.