HADOOP-7922. Improve some logging for client IPC failovers and StandbyExceptions. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-1623@1214082 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.HDFS-1623.txt

@@ -10,3 +10,6 @@ HADOOP-7774. HA: Administrative CLI to control HA daemons. (todd)
 
 HADOOP-7896. HA: if both NNs are in Standby mode, client needs to try failing
              back and forth several times with sleeps. (atm)
+
+HADOOP-7922. Improve some logging for client IPC failovers and
+             StandbyExceptions (todd)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryInvocationHandler.java

@@ -94,15 +94,29 @@ public Object invoke(Object proxy, Method method, Object[] args)
           return null;
         } else { // retry or failover
 
+          if (action.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY) {
+            String msg = "Exception while invoking " + method.getName()
+              + " of " + currentProxy.getClass()
+              + " after " + invocationFailoverCount + " fail over attempts."
+              + " Trying to fail over " + formatSleepMessage(action.delayMillis);
+            if (LOG.isDebugEnabled()) {
+              LOG.debug(msg, e);
+            } else {
+              LOG.warn(msg);
+            }
+          } else {
+            if(LOG.isDebugEnabled()) {
+              LOG.debug("Exception while invoking " + method.getName()
+                  + " of " + currentProxy.getClass() + ". Retrying " +
+                  formatSleepMessage(action.delayMillis), e);
+            }
+          }
+          
           if (action.delayMillis > 0) {
             ThreadUtil.sleepAtLeastIgnoreInterrupts(action.delayMillis);
           }
           
           if (action.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY) {
-            LOG.warn("Exception while invoking " + method.getName()
-                + " of " + currentProxy.getClass()
-                + " after " + invocationFailoverCount + " fail over attempts."
-                + " Trying to fail over.", e);
             // Make sure that concurrent failed method invocations only cause a
             // single actual fail over.
             synchronized (proxyProvider) {
@@ -118,12 +132,16 @@ public Object invoke(Object proxy, Method method, Object[] args)
             invocationFailoverCount++;
           }
         }
-        if(LOG.isDebugEnabled()) {
-          LOG.debug("Exception while invoking " + method.getName()
-              + " of " + currentProxy.getClass() + ". Retrying.", e);
       }
     }
   }
+  
+  private static String formatSleepMessage(long millis) {
+    if (millis > 0) {
+      return "after sleeping for " + millis + "ms.";
+    } else {
+      return "immediately.";
+    }
   }
   
   private Object invokeMethod(Method method, Object[] args) throws Throwable {

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

@@ -1616,6 +1616,10 @@ public Writable run() throws Exception {
               // on the server side, as opposed to just a normal exceptional
               // result.
               LOG.warn(logMsg, e);
+            } else if (e instanceof StandbyException) {
+              // Don't log the whole stack trace of these exceptions.
+              // Way too noisy!
+              LOG.info(logMsg);
             } else {
               LOG.info(logMsg, e);
             }