[HADOOP-14659] UGI getShortUserName does not need to search the Subject

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.9.0, 3.0.0-beta1, 2.8.2
• Component/s: common
• Target Version/s: 2.8.2
• Hadoop Flags: Reviewed
• Assignee: Daryn Sharp
• Reporter: Daryn Sharp
• Created: 13/Jul/17 20:17
• Updated: 25/Jul/17 04:41
• Resolved: 20/Jul/17 21:23

Description

UGI#getShortUserName searches the subject for the User instance. It's not cheap to iterate a synchronized set, copy matches into a new set, then iterating that set. The UGI ctor already set the User into a final field...