[HDFS-3280] DFSOutputStream.sync should not be synchronized

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.0.0-alpha
• Component/s: hdfs-client
• Target Version/s: 2.0.0-alpha
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 14/Apr/12 02:32
• Updated: 28/Sep/15 20:58
• Resolved: 14/Apr/12 02:52

Description

HDFS-895 added an optimization to make hflush() much faster by unsynchronizing it. But, we forgot to un-synchronize the deprecated sync() wrapper method. This makes the HBase WAL really slow on 0.23+ since it doesn't take advantage of HDFS-895 anymore.