[YARN-512] Log aggregation root directory check is more expensive than it needs to be

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.1.0-beta
• Fix Version/s: 2.1.0-beta
• Component/s: nodemanager
• Target Version/s: 2.1.0-beta
• Hadoop Flags: Reviewed
• Assignee: Maysam Yabandeh
• Reporter: Jason Darrell Lowe
• Created: 28/Mar/13 15:25
• Updated: 27/Aug/13 22:15
• Resolved: 29/May/13 14:29

Description

The log aggregation root directory check first does an exists call followed by a getFileStatus call. That effectively stats the file twice. It should just use getFileStatus and catch FileNotFoundException to handle the non-existent case.

In addition we may consider caching the presence of the directory rather than checking it each time a node aggregates logs for an application.