TEZ-4336: ShuffleScheduler should try to report the original exceptio…

…n (when shuffle becomes unhealthy) (apache#155) (Laszlo Bodor reviewed by Rajesh Balamohan)

(cherry picked from commit 6863a2d)

tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/InputAttemptFetchFailure.java

@@ -33,6 +33,7 @@ public class InputAttemptFetchFailure {
   private final InputAttemptIdentifier inputAttemptIdentifier;
   private final boolean isLocalFetch;
   private final boolean isDiskErrorAtSource;
+  private Throwable cause = null;
 
   public InputAttemptFetchFailure(InputAttemptIdentifier inputAttemptIdentifier) {
     this(inputAttemptIdentifier, false, false);
@@ -112,4 +113,13 @@ public String toString() {
     return String.format("%s, isLocalFetch: %s, isDiskErrorAtSource: %s",
         inputAttemptIdentifier.toString(), isLocalFetch, isDiskErrorAtSource);
   }
+
+  public InputAttemptFetchFailure withCause(Throwable throwable) {
+    this.cause = throwable;
+    return this;
+  }
+
+  public Throwable getCause() {
+    return cause;
+  }
 }

tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/FetcherOrderedGrouped.java

@@ -378,7 +378,7 @@ boolean setupConnection(MapHost host, Collection<InputAttemptIdentifier> attempt
       for (InputAttemptIdentifier left : remaining.values()) {
         // Need to be handling temporary glitches ..
         // Report read error to the AM to trigger source failure heuristics
-        scheduler.copyFailed(InputAttemptFetchFailure.fromAttempt(left), host, connectSucceeded,
+        scheduler.copyFailed(InputAttemptFetchFailure.fromAttempt(left).withCause(ie), host, connectSucceeded,
             !connectSucceeded);
       }
       return false;
@@ -738,7 +738,7 @@ protected void setupLocalDiskFetch(MapHost host) throws InterruptedException {
             if (!stopped) {
               hasFailures = true;
               ioErrs.increment(1);
-              scheduler.copyFailed(InputAttemptFetchFailure.fromLocalFetchFailure(srcAttemptId),
+              scheduler.copyFailed(InputAttemptFetchFailure.fromLocalFetchFailure(srcAttemptId).withCause(e),
                   host, true, false);
               LOG.warn("Failed to read local disk output of " + srcAttemptId + " from " +
                   host.getHostIdentifier(), e);

tez-runtime-library/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/ShuffleScheduler.java

@@ -178,6 +178,7 @@ enum ShuffleErrors {
   private final Referee referee;
   @VisibleForTesting
   final Map<InputAttemptIdentifier, IntWritable> failureCounts = new HashMap<InputAttemptIdentifier,IntWritable>();
+
   final Set<HostPort> uniqueHosts = Sets.newHashSet();
   private final Map<HostPort,IntWritable> hostFailures = new HashMap<HostPort,IntWritable>();
   private final InputContext inputContext;
@@ -792,7 +793,7 @@ public synchronized void copyFailed(InputAttemptFetchFailure fetchFailure, MapHo
     }
 
     //Restart consumer in case shuffle is not healthy
-    if (!isShuffleHealthy(fetchFailure.getInputAttemptIdentifier())) {
+    if (!isShuffleHealthy(fetchFailure)) {
       return;
     }
 
@@ -1006,8 +1007,8 @@ private boolean isFetcherHealthy(String logContext) {
     return fetcherHealthy;
   }
 
-  boolean isShuffleHealthy(InputAttemptIdentifier srcAttempt) {
-
+  boolean isShuffleHealthy(InputAttemptFetchFailure fetchFailure) {
+    InputAttemptIdentifier srcAttempt = fetchFailure.getInputAttemptIdentifier();
     if (isAbortLimitExceeedFor(srcAttempt)) {
       return false;
     }
@@ -1049,13 +1050,15 @@ boolean isShuffleHealthy(InputAttemptIdentifier srcAttempt) {
           + ", pendingInputs=" + (numInputs - doneMaps)
           + ", fetcherHealthy=" + fetcherHealthy
           + ", reducerProgressedEnough=" + reducerProgressedEnough
-          + ", reducerStalled=" + reducerStalled);
+          + ", reducerStalled=" + reducerStalled
+          + ", hostFailures=" + hostFailures)
+          + "]";
       LOG.error(errorMsg);
       if (LOG.isDebugEnabled()) {
         LOG.debug("Host failures=" + hostFailures.keySet());
       }
       // Shuffle knows how to deal with failures post shutdown via the onFailure hook
-      exceptionReporter.reportException(new IOException(errorMsg));
+      exceptionReporter.reportException(new IOException(errorMsg, fetchFailure.getCause()));
       return false;
     }
     return true;