HDFS-9886. Configuration properties for hedged read is broken. Contributed by Akira AJISAKA.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/HdfsClientConfigKeys.java

@@ -377,6 +377,8 @@ public interface HdfsClientConfigKeys {
 
   /** dfs.client.hedged.read configuration properties */
   interface HedgedRead {
+    String PREFIX = HdfsClientConfigKeys.PREFIX + "hedged.read.";
+
     String  THRESHOLD_MILLIS_KEY = PREFIX + "threshold.millis";
     long    THRESHOLD_MILLIS_DEFAULT = 500;
     String  THREADPOOL_SIZE_KEY = PREFIX + "threadpool.size";

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1920,6 +1920,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-9881. DistributedFileSystem#getTrashRoot returns incorrect path for
     encryption zones. (wang)
 
+    HDFS-9886. Configuration properties for hedged read is broken. 
+    (Akira AJISAKA via zhz)
+
 Release 2.7.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES