[MAPREDUCE-2239] BlockPlacementPolicyRaid should call getBlockLocations only when necessary

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.0
• Fix Version/s: 0.23.0
• Component/s: contrib/raid
• Hadoop Flags: Reviewed
• Assignee: Scott Chen
• Reporter: Scott Chen
• Created: 04/Jan/11 01:48
• Updated: 15/Nov/11 00:49
• Resolved: 04/Mar/11 18:07

Description

Currently BlockPlacementPolicyRaid calls getBlockLocations for every chooseTarget().
This puts pressure on NameNode. We should avoid calling if this file is not raided or a parity file.