Fix and UT for testing segment analysis merge

processing/src/main/java/io/druid/query/metadata/SegmentMetadataQueryQueryToolChest.java

@@ -36,7 +36,6 @@ import com.metamx.emitter.service.ServiceMetricEvent;
 import io.druid.collections.OrderedMergeSequence;
 import io.druid.common.guava.CombiningSequence;
 import io.druid.common.utils.JodaUtils;
-import io.druid.data.input.Row;
 import io.druid.query.CacheStrategy;
 import io.druid.query.DruidMetrics;
 import io.druid.query.Query;
@@ -53,6 +52,7 @@ import org.joda.time.Interval;
 
 import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -149,7 +149,7 @@ public class SegmentMetadataQueryQueryToolChest extends QueryToolChest<SegmentAn
 
             List<Interval> newIntervals = null;
             if (query.hasInterval()) {
-              newIntervals = arg1.getIntervals();
+              newIntervals = new ArrayList<>(arg1.getIntervals());
               newIntervals.addAll(arg2.getIntervals());
             }
 

processing/src/test/java/io/druid/query/metadata/SegmentMetadataQueryTest.java

@@ -122,6 +122,53 @@ public class SegmentMetadataQueryTest
     Assert.assertEquals(Arrays.asList(expectedSegmentAnalysis), results);
   }
 
+  @Test
+  public void testSegmentMetadataQueryWithDefaultAnalysisMerge()
+  {
+    SegmentAnalysis mergedSegmentAnalysis = new SegmentAnalysis(
+        "merged",
+        ImmutableList.of(
+            expectedSegmentAnalysis.getIntervals().get(0),
+            expectedSegmentAnalysis.getIntervals().get(0)
+        ),
+        ImmutableMap.of(
+            "placement",
+            new ColumnAnalysis(
+                ValueType.STRING.toString(),
+                21762,
+                1,
+                null
+            )
+        ),
+        expectedSegmentAnalysis.getSize()*2,
+        expectedSegmentAnalysis.getNumRows()*2
+    );
+
+    QueryToolChest toolChest = factory.getToolchest();
+
+    QueryRunner singleSegmentQueryRunner = toolChest.preMergeQueryDecoration(runner);
+    ExecutorService exec = Executors.newCachedThreadPool();
+    QueryRunner myRunner = new FinalizeResultsQueryRunner<>(
+        toolChest.mergeResults(
+            factory.mergeRunners(
+                Executors.newCachedThreadPool(),
+                Lists.<QueryRunner<SegmentAnalysis>>newArrayList(singleSegmentQueryRunner, singleSegmentQueryRunner)
+            )
+        ),
+        toolChest
+    );
+
+    TestHelper.assertExpectedObjects(
+        ImmutableList.of(mergedSegmentAnalysis),
+        myRunner.run(
+            testQuery,
+            Maps.newHashMap()
+        ),
+        "failed SegmentMetadata bySegment query"
+    );
+    exec.shutdownNow();
+  }
+
   @Test
   public void testBySegmentResults()
   {