fix retry logic and change the default value of retry to 0

processing/src/main/java/io/druid/query/RetryQueryRunner.java

@@ -20,11 +20,11 @@
 package io.druid.query;
 
 import com.metamx.common.guava.Sequence;
-import com.metamx.common.guava.Sequences;
-import io.druid.query.spec.MultipleSpecificSegmentSpec;
+import com.metamx.common.guava.Yielder;
+import com.metamx.common.guava.YieldingAccumulator;
+import com.metamx.common.guava.YieldingSequenceBase;
 import io.druid.segment.SegmentMissingException;
 
-import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 
@@ -35,7 +35,11 @@ public class RetryQueryRunner<T> implements QueryRunner<T>
   private final QueryToolChest<T, Query<T>> toolChest;
   private final RetryQueryRunnerConfig config;
 
-  public RetryQueryRunner(QueryRunner<T> baseRunner, QueryToolChest<T, Query<T>> toolChest, RetryQueryRunnerConfig config)
+  public RetryQueryRunner(
+      QueryRunner<T> baseRunner,
+      QueryToolChest<T, Query<T>> toolChest,
+      RetryQueryRunnerConfig config
+  )
   {
     this.baseRunner = baseRunner;
     this.toolChest = toolChest;
@@ -43,36 +47,42 @@ public class RetryQueryRunner<T> implements QueryRunner<T>
   }
 
   @Override
-  public Sequence<T> run(final Query<T> query, Map<String, Object> context)
+  public Sequence<T> run(final Query<T> query, final Map<String, Object> context)
   {
-    Sequence<T> returningSeq = baseRunner.run(query, context);
+    final Sequence<T> returningSeq = baseRunner.run(query, context);
 
+    return new YieldingSequenceBase<T>()
+    {
+      @Override
+      public <OutType> Yielder<OutType> toYielder(
+          OutType initValue, YieldingAccumulator<OutType, T> accumulator
+      )
+      {
+        Yielder<OutType> yielder = returningSeq.toYielder(initValue, accumulator);
 
-    for (int i = config.numTries(); i > 0 && !((List)context.get(missingSegments)).isEmpty(); i--) {
-        List<SegmentDescriptor> segList= (List<SegmentDescriptor>)context.get(missingSegments);
-        ((List)context.get(missingSegments)).clear();
-        returningSeq = toolChest.mergeSequences(
-            Sequences.simple(
-                Arrays.asList(
-                    returningSeq,
-                    baseRunner.run(
-                        query.withQuerySegmentSpec(new MultipleSpecificSegmentSpec(segList)),
-                        context
-                    )
-                )
-            )
-        );
-    }
+        if (((List) context.get(missingSegments)).isEmpty()) {
+          return yielder;
+        }
 
-    if (!config.returnPartialResults() && !((List)context.get(missingSegments)).isEmpty()) {
-      String failedSegments = "";
-      for (SegmentDescriptor segment : (List<SegmentDescriptor>) context.get("missingSegments")) {
-        failedSegments = failedSegments + segment.toString() + " ";
+        for (int i = config.numTries(); i > 0 && !((List) context.get(missingSegments)).isEmpty(); i--) {
+          ((List) context.get(missingSegments)).clear();
+          yielder = baseRunner.run(query, context).toYielder(initValue, accumulator);
+          if (((List) context.get(missingSegments)).isEmpty()) {
+            break;
+          }
+        }
+
+        if (!config.returnPartialResults() && !((List) context.get(missingSegments)).isEmpty()) {
+          String failedSegments = "";
+          for (SegmentDescriptor segment : (List<SegmentDescriptor>) context.get("missingSegments")) {
+            failedSegments = failedSegments + segment.toString() + " ";
+          }
+          throw new SegmentMissingException("The following segments are missing: " + failedSegments);
+        }
+
+        return yielder;
       }
-      throw new SegmentMissingException("The following segments are missing: " + failedSegments);
-    }
-
-    return returningSeq;
+    };
   }
 }
 

processing/src/main/java/io/druid/query/RetryQueryRunnerConfig.java

@@ -24,7 +24,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 public class RetryQueryRunnerConfig
 {
   @JsonProperty
-  private int numTries = 1;
+  private int numTries = 0;
   private boolean returnPartialResults = false;
 
   public int numTries() { return numTries; }

server/src/main/java/io/druid/client/CachingClusteredClient.java

@@ -253,6 +253,7 @@ public class CachingClusteredClient<T> implements QueryRunner<T>
             addSequencesFromServer(listOfSequences);
             addSequencesFromCache(listOfSequences);
 
+
             Collections.sort(
                 listOfSequences,
                 Ordering.natural().onResultOf(Pair.<DateTime, Sequence<T>>lhsFn())