[HDFS-9221] HdfsServerConstants#ReplicaState#getState should avoid calling values() since it creates a temporary array

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.7.1
• Fix Version/s: 2.8.0, 2.7.2, 3.0.0-alpha1
• Component/s: performance
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: Staffan Friberg
• Reporter: Staffan Friberg
• Created: 09/Oct/15 18:03
• Updated: 06/Jan/17 07:31
• Resolved: 12/Oct/15 06:42

Description

When the BufferDecoder in BlockListAsLongs converts the stored value to a ReplicaState enum it calls ReplicaState.getState(int) unfortunately this method creates a ReplicaState[] for each call since it calls ReplicaState.values().

This patch creates a cached version of the values and thus avoid all allocation when doing the conversion.

Issue Links

• is related to: HDFS-8867 Enable optimized block reports
• is related to: HDFS-7435 PB encoding of block reports is very inefficient