HADOOP-9822. create constant MAX_CAPACITY in RetryCache rather than hard-coding 16 in RetryCache constructor. Contributed by Tsuyoshi Ozawa.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -1358,6 +1358,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-11149. TestZKFailoverController times out. (Steve Loughran
     via ozawa)
 
+    HADOOP-9822. Create constant MAX_CAPACITY in RetryCache rather than
+    hard-coding 16 in RetryCache constructor. (Tsuyoshi Ozawa via wheat9)
+
   OPTIMIZATIONS
 
     HADOOP-12051. ProtobufRpcEngine.invoke() should use Exception.toString()

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/RetryCache.java

@@ -46,6 +46,7 @@ import com.google.common.base.Preconditions;
 public class RetryCache {
   public static final Log LOG = LogFactory.getLog(RetryCache.class);
   private final RetryCacheMetrics retryCacheMetrics;
+  private static final int MAX_CAPACITY = 16;
 
   /**
    * CacheEntry is tracked using unique client ID and callId of the RPC request
@@ -194,7 +195,7 @@ public class RetryCache {
    */
   public RetryCache(String cacheName, double percentage, long expirationTime) {
     int capacity = LightWeightGSet.computeCapacity(percentage, cacheName);
-    capacity = capacity > 16 ? capacity : 16;
+    capacity = capacity > MAX_CAPACITY ? capacity : MAX_CAPACITY;
     this.set = new LightWeightCache<CacheEntry, CacheEntry>(capacity, capacity,
         expirationTime, 0);
     this.expirationTime = expirationTime;