diff --git a/processing/src/main/java/io/druid/query/BySegmentResultValue.java b/processing/src/main/java/io/druid/query/BySegmentResultValue.java
index 3d2dc0802f3..fdc27d9c652 100644
--- a/processing/src/main/java/io/druid/query/BySegmentResultValue.java
+++ b/processing/src/main/java/io/druid/query/BySegmentResultValue.java
@@ -19,15 +19,17 @@
 
 package io.druid.query;
 
+import org.joda.time.Interval;
+
 import java.util.List;
 
 /**
  */
 public interface BySegmentResultValue<T>
 {
-  public List<Result<T>> getResults();
+  public List<T> getResults();
 
   public String getSegmentId();
 
-  public String getIntervalString();
+  public Interval getInterval();
 }
diff --git a/processing/src/main/java/io/druid/query/BySegmentResultValueClass.java b/processing/src/main/java/io/druid/query/BySegmentResultValueClass.java
index 3a3544cf47a..0d779733e66 100644
--- a/processing/src/main/java/io/druid/query/BySegmentResultValueClass.java
+++ b/processing/src/main/java/io/druid/query/BySegmentResultValueClass.java
@@ -26,7 +26,7 @@ import java.util.List;
 
 /**
  */
-public class BySegmentResultValueClass<T>
+public class BySegmentResultValueClass<T> implements BySegmentResultValue<T>
 {
   private final List<T> results;
   private final String segmentId;
@@ -43,18 +43,21 @@ public class BySegmentResultValueClass<T>
     this.interval = interval;
   }
 
+  @Override
   @JsonProperty("results")
   public List<T> getResults()
   {
     return results;
   }
 
+  @Override
   @JsonProperty("segment")
   public String getSegmentId()
   {
     return segmentId;
   }
 
+  @Override
   @JsonProperty("interval")
   public Interval getInterval()
   {
diff --git a/processing/src/main/java/io/druid/query/FinalizeResultsQueryRunner.java b/processing/src/main/java/io/druid/query/FinalizeResultsQueryRunner.java
index 10bff0a65e2..1794024b60c 100644
--- a/processing/src/main/java/io/druid/query/FinalizeResultsQueryRunner.java
+++ b/processing/src/main/java/io/druid/query/FinalizeResultsQueryRunner.java
@@ -84,7 +84,7 @@ public class FinalizeResultsQueryRunner<T> implements QueryRunner<T>
             throw new ISE("Cannot have a null result!");
           }
 
-          BySegmentResultValueClass<T> resultsClass = result.getValue();
+          BySegmentResultValue<T> resultsClass = result.getValue();
 
           return (T) new Result<BySegmentResultValueClass>(
               result.getTimestamp(),
diff --git a/processing/src/main/java/io/druid/query/search/BySegmentSearchResultValue.java b/processing/src/main/java/io/druid/query/search/BySegmentSearchResultValue.java
index 0ecbdf509c2..c77b25f19bd 100644
--- a/processing/src/main/java/io/druid/query/search/BySegmentSearchResultValue.java
+++ b/processing/src/main/java/io/druid/query/search/BySegmentSearchResultValue.java
@@ -24,28 +24,30 @@ import com.fasterxml.jackson.annotation.JsonValue;
 import io.druid.query.BySegmentResultValue;
 import io.druid.query.Result;
 import io.druid.query.search.search.SearchHit;
+import org.joda.time.Interval;
 
 import java.util.List;
 
 /**
  */
-public class BySegmentSearchResultValue extends SearchResultValue implements BySegmentResultValue<SearchResultValue>
+public class BySegmentSearchResultValue extends SearchResultValue
+    implements BySegmentResultValue<Result<SearchResultValue>>
 {
   private final List<Result<SearchResultValue>> results;
   private final String segmentId;
-  private final String intervalString;
+  private final Interval interval;
 
   public BySegmentSearchResultValue(
       @JsonProperty("results") List<Result<SearchResultValue>> results,
       @JsonProperty("segment") String segmentId,
-      @JsonProperty("interval") String intervalString
+      @JsonProperty("interval") Interval interval
   )
   {
     super(null);
 
     this.results = results;
     this.segmentId = segmentId;
-    this.intervalString = intervalString;
+    this.interval = interval;
   }
 
   @Override
@@ -71,9 +73,9 @@ public class BySegmentSearchResultValue extends SearchResultValue implements ByS
 
   @Override
   @JsonProperty("interval")
-  public String getIntervalString()
+  public Interval getInterval()
   {
-    return intervalString;
+    return interval;
   }
 
   @Override
@@ -82,7 +84,7 @@ public class BySegmentSearchResultValue extends SearchResultValue implements ByS
     return "BySegmentSearchResultValue{" +
            "results=" + results +
            ", segmentId='" + segmentId + '\'' +
-           ", intervalString='" + intervalString + '\'' +
+           ", interval='" + interval.toString() + '\'' +
            '}';
   }
 }
diff --git a/processing/src/main/java/io/druid/query/search/SearchQueryQueryToolChest.java b/processing/src/main/java/io/druid/query/search/SearchQueryQueryToolChest.java
index d6bcd61cfe1..79d9686cee8 100644
--- a/processing/src/main/java/io/druid/query/search/SearchQueryQueryToolChest.java
+++ b/processing/src/main/java/io/druid/query/search/SearchQueryQueryToolChest.java
@@ -329,7 +329,7 @@ public class SearchQueryQueryToolChest extends QueryToolChest<Result<SearchResul
                             }
                         ),
                         value.getSegmentId(),
-                        value.getIntervalString()
+                        value.getInterval()
                     )
                 );
               }
diff --git a/processing/src/main/java/io/druid/query/topn/BySegmentTopNResultValue.java b/processing/src/main/java/io/druid/query/topn/BySegmentTopNResultValue.java
index 56849d6fd47..009676eb8f9 100644
--- a/processing/src/main/java/io/druid/query/topn/BySegmentTopNResultValue.java
+++ b/processing/src/main/java/io/druid/query/topn/BySegmentTopNResultValue.java
@@ -23,30 +23,32 @@ import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonValue;
 import io.druid.query.BySegmentResultValue;
+import io.druid.query.BySegmentResultValueClass;
 import io.druid.query.Result;
+import org.joda.time.Interval;
 
 import java.util.List;
 
 /**
  */
-public class BySegmentTopNResultValue extends TopNResultValue implements BySegmentResultValue<TopNResultValue>
+public class BySegmentTopNResultValue extends TopNResultValue implements BySegmentResultValue<Result<TopNResultValue>>
 {
   private final List<Result<TopNResultValue>> results;
   private final String segmentId;
-  private final String intervalString;
+  private final Interval interval;
 
   @JsonCreator
   public BySegmentTopNResultValue(
       @JsonProperty("results") List<Result<TopNResultValue>> results,
       @JsonProperty("segment") String segmentId,
-      @JsonProperty("interval") String intervalString
+      @JsonProperty("interval") Interval interval
   )
   {
     super(null);
 
     this.results = results;
     this.segmentId = segmentId;
-    this.intervalString = intervalString;
+    this.interval = interval;
   }
 
   @Override
@@ -73,9 +75,9 @@ public class BySegmentTopNResultValue extends TopNResultValue implements BySegme
 
   @Override
   @JsonProperty("interval")
-  public String getIntervalString()
+  public Interval getInterval()
   {
-    return intervalString;
+    return interval;
   }
 
   @Override
@@ -84,7 +86,7 @@ public class BySegmentTopNResultValue extends TopNResultValue implements BySegme
     return "BySegmentTopNResultValue{" +
            "results=" + results +
            ", segmentId='" + segmentId + '\'' +
-           ", intervalString='" + intervalString + '\'' +
+           ", interval='" + interval.toString() + '\'' +
            '}';
   }
 }
diff --git a/processing/src/main/java/io/druid/query/topn/TopNQueryQueryToolChest.java b/processing/src/main/java/io/druid/query/topn/TopNQueryQueryToolChest.java
index 165e3149456..b8babee2d12 100644
--- a/processing/src/main/java/io/druid/query/topn/TopNQueryQueryToolChest.java
+++ b/processing/src/main/java/io/druid/query/topn/TopNQueryQueryToolChest.java
@@ -35,6 +35,8 @@ import com.metamx.common.guava.nary.BinaryFn;
 import com.metamx.emitter.service.ServiceMetricEvent;
 import io.druid.collections.OrderedMergeSequence;
 import io.druid.granularity.QueryGranularity;
+import io.druid.query.BySegmentResultValue;
+import io.druid.query.BySegmentResultValueClass;
 import io.druid.query.CacheStrategy;
 import io.druid.query.IntervalChunkingQueryRunner;
 import io.druid.query.Query;
@@ -433,7 +435,8 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
             public Result<TopNResultValue> apply(Result<TopNResultValue> input)
             {
               if (isBySegment) {
-                BySegmentTopNResultValue value = (BySegmentTopNResultValue) input.getValue();
+                BySegmentResultValue<Result<TopNResultValue>> value = (BySegmentResultValue<Result<TopNResultValue>>) input
+                    .getValue();
 
                 return new Result<TopNResultValue>(
                     input.getTimestamp(),
@@ -460,7 +463,7 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
                             }
                         ),
                         value.getSegmentId(),
-                        value.getIntervalString()
+                        value.getInterval()
                     )
                 );
               }
diff --git a/processing/src/test/java/io/druid/query/topn/TopNQueryRunnerTest.java b/processing/src/test/java/io/druid/query/topn/TopNQueryRunnerTest.java
index 2e978dd408f..acc1a7bb382 100644
--- a/processing/src/test/java/io/druid/query/topn/TopNQueryRunnerTest.java
+++ b/processing/src/test/java/io/druid/query/topn/TopNQueryRunnerTest.java
@@ -19,10 +19,12 @@
 
 package io.druid.query.topn;
 
+import com.google.common.base.Function;
 import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
+import com.metamx.common.guava.Sequence;
 import com.metamx.common.guava.Sequences;
 import io.druid.collections.StupidPool;
 import io.druid.query.BySegmentResultValueClass;
@@ -47,6 +49,7 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 
+import javax.annotation.Nullable;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
@@ -167,7 +170,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -231,7 +234,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -296,11 +299,89 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
 
+  @Test
+  public void testTopNBySegment()
+  {
+
+    final HashMap<String, Object> specialContext = new HashMap<String, Object>();
+    specialContext.put("bySegment", "true");
+    TopNQuery query = new TopNQueryBuilder()
+        .dataSource(QueryRunnerTestHelper.dataSource)
+        .granularity(QueryRunnerTestHelper.allGran)
+        .dimension(marketDimension)
+        .metric(QueryRunnerTestHelper.indexMetric)
+        .threshold(4)
+        .intervals(QueryRunnerTestHelper.firstToThird)
+        .aggregators(QueryRunnerTestHelper.commonAggregators)
+        .postAggregators(Arrays.<PostAggregator>asList(QueryRunnerTestHelper.addRowsIndexConstant))
+        .context(specialContext)
+        .build();
+
+
+    List<Result<TopNResultValue>> expectedResults = Arrays.asList(
+        new Result<TopNResultValue>(
+            new DateTime("2011-04-01T00:00:00.000Z"),
+            new TopNResultValue(
+                Arrays.<Map<String, Object>>asList(
+                    ImmutableMap.<String, Object>of(
+                        "addRowsIndexConstant", 5356.814697265625D,
+                        "index", 5351.814697265625D,
+                        marketDimension, "total_market",
+                        "uniques", QueryRunnerTestHelper.UNIQUES_2,
+                        "rows", 4L
+                    ),
+                    ImmutableMap.<String, Object>of(
+                        "addRowsIndexConstant", 4880.669677734375D,
+                        "index", 4875.669677734375D,
+                        marketDimension, "upfront",
+                        "uniques", QueryRunnerTestHelper.UNIQUES_2,
+                        "rows", 4L
+                    ),
+                    ImmutableMap.<String, Object>of(
+                        "addRowsIndexConstant", 2250.8768157958984D,
+                        "index", 2231.8768157958984D,
+                        marketDimension, "spot",
+                        "uniques", QueryRunnerTestHelper.UNIQUES_9,
+                        "rows", 18L
+                    )
+                )
+            )
+        )
+    );
+    Sequence<Result<TopNResultValue>> results = new TopNQueryQueryToolChest(new TopNQueryConfig()).postMergeQueryDecoration(
+        runner
+    ).run(
+        query,
+        specialContext
+    );
+    List<Result<BySegmentTopNResultValue>> resultList = Sequences.toList(
+        Sequences.map(
+            results, new Function<Result<TopNResultValue>, Result<BySegmentTopNResultValue>>()
+            {
+
+              @Nullable
+              @Override
+              public Result<BySegmentTopNResultValue> apply(
+                  Result<TopNResultValue> input
+              )
+              {
+                return new Result<BySegmentTopNResultValue>(
+                    input.getTimestamp(),
+                    (BySegmentTopNResultValue) input.getValue()
+                );
+              }
+            }
+        ),
+        Lists.<Result<BySegmentTopNResultValue>>newArrayList()
+    );
+    TestHelper.assertExpectedResults(expectedResults, resultList.get(0).getValue().getResults());
+  }
+
   @Test
   public void testTopN()
   {
@@ -346,7 +427,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -395,7 +476,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -444,7 +525,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -486,7 +567,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -521,7 +602,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -570,7 +651,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -623,7 +704,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -665,7 +746,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -683,7 +764,7 @@ public class TopNQueryRunnerTest
         .aggregators(QueryRunnerTestHelper.commonAggregators)
         .postAggregators(Arrays.<PostAggregator>asList(QueryRunnerTestHelper.addRowsIndexConstant))
         .build();
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(
         Lists.<Result<TopNResultValue>>newArrayList(
             new Result<TopNResultValue>(
@@ -722,7 +803,7 @@ public class TopNQueryRunnerTest
         .aggregators(QueryRunnerTestHelper.commonAggregators)
         .postAggregators(Arrays.<PostAggregator>asList(QueryRunnerTestHelper.addRowsIndexConstant))
         .build();
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(
         Lists.<Result<TopNResultValue>>newArrayList(
             new Result<TopNResultValue>(
@@ -748,7 +829,7 @@ public class TopNQueryRunnerTest
         .aggregators(QueryRunnerTestHelper.commonAggregators)
         .postAggregators(Arrays.<PostAggregator>asList(QueryRunnerTestHelper.addRowsIndexConstant))
         .build();
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(
         Sequences.toList(
             runner.run(
@@ -783,7 +864,7 @@ public class TopNQueryRunnerTest
         .aggregators(QueryRunnerTestHelper.commonAggregators)
         .postAggregators(Arrays.<PostAggregator>asList(QueryRunnerTestHelper.addRowsIndexConstant))
         .build();
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(
         Sequences.toList(
             runner.run(
@@ -843,7 +924,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -892,7 +973,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -948,7 +1029,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -996,7 +1077,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1037,7 +1118,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1078,7 +1159,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1119,7 +1200,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1160,7 +1241,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1212,7 +1293,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1264,7 +1345,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1316,7 +1397,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1361,7 +1442,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1407,7 +1488,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1452,7 +1533,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1501,7 +1582,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1586,7 +1667,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 
@@ -1669,7 +1750,7 @@ public class TopNQueryRunnerTest
             )
         )
     );
-    HashMap<String,Object> context = new HashMap<String, Object>();
+    HashMap<String, Object> context = new HashMap<String, Object>();
     TestHelper.assertExpectedResults(expectedResults, runner.run(query, context));
   }
 }
diff --git a/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java b/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java
index 38ec31c1bc8..f84607e659b 100644
--- a/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java
+++ b/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java
@@ -87,7 +87,7 @@ public class ClientQuerySegmentWalker implements QuerySegmentWalker
     final FinalizeResultsQueryRunner<T> baseRunner = new FinalizeResultsQueryRunner<T>(
         toolChest.postMergeQueryDecoration(
             toolChest.mergeResults(
-                new UnionQueryRunner<>(
+                new UnionQueryRunner<T>(
                     new MetricsEmittingQueryRunner<T>(
                         emitter,
                         new Function<Query<T>, ServiceMetricEvent.Builder>()