[HADOOP-11785] Reduce number of listStatus operation in distcp buildListing()

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha1
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: tools/distcp
• Assignee: Zoran Dimitrijevic
• Reporter: Zoran Dimitrijevic
• Due: 07/Apr/15
• Created: 01/Apr/15 17:00
• Updated: 30/Aug/16 01:29
• Resolved: 03/Apr/15 21:09

Description

Distcp was taking long time in copyListing.buildListing() for large source trees (I was using source of 1.5M files in a tree of about 50K directories). For input at s3 buildListing was taking more than one hour. I've noticed a performance bug in the current code which does listStatus twice for each directory which doubles number of RPCs in some cases (if most directories do not contain >1000 files).