diff --git a/common/src/main/java/io/druid/timeline/TimelineLookup.java b/common/src/main/java/io/druid/timeline/TimelineLookup.java
new file mode 100644
index 00000000000..2fc343ac9b2
--- /dev/null
+++ b/common/src/main/java/io/druid/timeline/TimelineLookup.java
@@ -0,0 +1,44 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.timeline;
+
+import io.druid.timeline.partition.PartitionHolder;
+import org.joda.time.Interval;
+
+import java.util.List;
+
+
+public interface TimelineLookup<VersionType, ObjectType>
+{
+
+  /**
+   * Does a lookup for the objects representing the given time interval.  Will *only* return
+   * PartitionHolders that are complete.
+   *
+   * @param interval interval to find objects for
+   *
+   * @return Holders representing the interval that the objects exist for, PartitionHolders
+   *         are guaranteed to be complete
+   */
+  public List<TimelineObjectHolder<VersionType, ObjectType>> lookup(Interval interval);
+
+  public PartitionHolder<ObjectType> findEntry(Interval interval, VersionType version);
+
+}
diff --git a/common/src/main/java/io/druid/timeline/UnionTimeLineLookup.java b/common/src/main/java/io/druid/timeline/UnionTimeLineLookup.java
new file mode 100644
index 00000000000..d5cf8f89f08
--- /dev/null
+++ b/common/src/main/java/io/druid/timeline/UnionTimeLineLookup.java
@@ -0,0 +1,54 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.timeline;
+
+import com.google.common.collect.Lists;
+import io.druid.timeline.partition.PartitionHolder;
+import org.joda.time.Interval;
+
+import java.util.List;
+
+
+public class UnionTimeLineLookup<VersionType, ObjectType> implements TimelineLookup<VersionType, ObjectType>
+{
+  Iterable<TimelineLookup<VersionType,ObjectType>> delegates;
+  public UnionTimeLineLookup( Iterable<TimelineLookup<VersionType,ObjectType>> delegates){
+    this.delegates = delegates;
+  }
+  @Override
+  public List<TimelineObjectHolder<VersionType, ObjectType>> lookup(Interval interval)
+  {
+    List<TimelineObjectHolder<VersionType, ObjectType>> rv = Lists.newArrayList();
+    for(TimelineLookup<VersionType,ObjectType> delegate : delegates){
+      rv.addAll(delegate.lookup(interval));
+    }
+    return rv;
+  }
+
+  public PartitionHolder<ObjectType> findEntry(Interval interval, VersionType version){
+    for(TimelineLookup<VersionType,ObjectType> delegate : delegates){
+      final PartitionHolder<ObjectType> entry = delegate.findEntry(interval, version);
+      if(entry != null){
+        return entry;
+      }
+    }
+    return null;
+  }
+}
diff --git a/common/src/main/java/io/druid/timeline/VersionedIntervalTimeline.java b/common/src/main/java/io/druid/timeline/VersionedIntervalTimeline.java
index 903480e2dac..1c73782c8d5 100644
--- a/common/src/main/java/io/druid/timeline/VersionedIntervalTimeline.java
+++ b/common/src/main/java/io/druid/timeline/VersionedIntervalTimeline.java
@@ -58,7 +58,7 @@ import java.util.concurrent.locks.ReentrantReadWriteLock;
  * to achieve "atomic" updates.  First add new items, then check if those items caused anything to be overshadowed, if
  * so, remove the overshadowed elements and you have effectively updated your data set without any user impact.
  */
-public class VersionedIntervalTimeline<VersionType, ObjectType>
+public class VersionedIntervalTimeline<VersionType, ObjectType> implements TimelineLookup<VersionType, ObjectType>
 {
   private static final Logger log = new Logger(VersionedIntervalTimeline.class);
 
diff --git a/processing/src/main/java/io/druid/query/UnionQueryRunner.java b/processing/src/main/java/io/druid/query/UnionQueryRunner.java
index f14bb180f62..09eba3bf5be 100644
--- a/processing/src/main/java/io/druid/query/UnionQueryRunner.java
+++ b/processing/src/main/java/io/druid/query/UnionQueryRunner.java
@@ -22,49 +22,47 @@
 package io.druid.query;
 
 import com.google.common.base.Function;
+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 java.util.List;
+
 public class UnionQueryRunner<T> implements QueryRunner<T>
 {
-  private final QueryRunner<T> baseRunner;
+  private final Iterable<QueryRunner<T>> baseRunners;
   private final QueryToolChest<T, Query<T>> toolChest;
 
   public UnionQueryRunner(
-      QueryRunner<T> baseRunner,
+      Iterable<QueryRunner<T>> baseRunners,
       QueryToolChest<T, Query<T>> toolChest
   )
   {
-    this.baseRunner = baseRunner;
+    this.baseRunners = baseRunners;
     this.toolChest = toolChest;
   }
 
   @Override
   public Sequence<T> run(final Query<T> query)
   {
-    DataSource dataSource = query.getDataSource();
-    if (dataSource instanceof UnionDataSource) {
       return toolChest.mergeSequencesUnordered(
           Sequences.simple(
-              Lists.transform(
-                  ((UnionDataSource) dataSource).getDataSources(),
-                  new Function<DataSource, Sequence<T>>()
+              Iterables.transform(
+                  baseRunners,
+                  new Function<QueryRunner<T>, Sequence<T>>()
                   {
                     @Override
-                    public Sequence<T> apply(DataSource singleSource)
+                    public Sequence<T> apply(QueryRunner<T> singleRunner)
                     {
-                      return baseRunner.run(
-                          query.withDataSource(singleSource)
+                      return singleRunner.run(
+                          query
                       );
                     }
                   }
               )
           )
       );
-    } else {
-      return baseRunner.run(query);
-    }
   }
 
 }
diff --git a/processing/src/test/java/io/druid/query/QueryRunnerTestHelper.java b/processing/src/test/java/io/druid/query/QueryRunnerTestHelper.java
index deeaff563e8..15ba20ddb50 100644
--- a/processing/src/test/java/io/druid/query/QueryRunnerTestHelper.java
+++ b/processing/src/test/java/io/druid/query/QueryRunnerTestHelper.java
@@ -20,6 +20,7 @@
 package io.druid.query;
 
 import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.util.concurrent.ListenableFuture;
 import io.druid.granularity.QueryGranularity;
@@ -70,14 +71,14 @@ public class QueryRunnerTestHelper
   public static final UnionDataSource unionDataSource = new UnionDataSource(
       Lists.transform(
           Lists.newArrayList(dataSource, dataSource, dataSource, dataSource), new Function<String, TableDataSource>()
-      {
-        @Nullable
-        @Override
-        public TableDataSource apply(@Nullable String input)
-        {
-          return new TableDataSource(input);
-        }
-      }
+          {
+            @Nullable
+            @Override
+            public TableDataSource apply(@Nullable String input)
+            {
+              return new TableDataSource(input);
+            }
+          }
       )
   );
   public static final QueryGranularity dayGran = QueryGranularity.DAY;
@@ -214,7 +215,8 @@ public class QueryRunnerTestHelper
 
   @SuppressWarnings("unchecked")
   public static Collection<?> makeUnionQueryRunners(
-      QueryRunnerFactory factory
+      QueryRunnerFactory factory,
+      DataSource unionDataSource
   )
       throws IOException
   {
@@ -224,13 +226,17 @@ public class QueryRunnerTestHelper
     return Arrays.asList(
         new Object[][]{
             {
-                makeUnionQueryRunner(factory, new IncrementalIndexSegment(rtIndex, segmentId))
+                makeUnionQueryRunner(factory, new IncrementalIndexSegment(rtIndex, segmentId), unionDataSource)
             },
             {
-                makeUnionQueryRunner(factory, new QueryableIndexSegment(segmentId, mMappedTestIndex))
+                makeUnionQueryRunner(factory, new QueryableIndexSegment(segmentId, mMappedTestIndex), unionDataSource)
             },
             {
-                makeUnionQueryRunner(factory, new QueryableIndexSegment(segmentId, mergedRealtimeIndex))
+                makeUnionQueryRunner(
+                    factory,
+                    new QueryableIndexSegment(segmentId, mergedRealtimeIndex),
+                    unionDataSource
+                )
             }
         }
     );
@@ -251,17 +257,28 @@ public class QueryRunnerTestHelper
   }
 
   public static <T> QueryRunner<T> makeUnionQueryRunner(
-      QueryRunnerFactory<T, Query<T>> factory,
-      Segment adapter
+      final QueryRunnerFactory<T, Query<T>> factory,
+      final Segment adapter,
+      final DataSource unionDataSource
   )
   {
     return new FinalizeResultsQueryRunner<T>(
         factory.getToolchest().postMergeQueryDecoration(
             factory.getToolchest().mergeResults(
                 new UnionQueryRunner<T>(
-                    new BySegmentQueryRunner<T>(
-                        segmentId, adapter.getDataInterval().getStart(),
-                        factory.createRunner(adapter)
+                    Iterables.transform(
+                        unionDataSource.getNames(), new Function<String, QueryRunner<T>>()
+                        {
+                          @Nullable
+                          @Override
+                          public QueryRunner<T> apply(@Nullable String input)
+                          {
+                            return new BySegmentQueryRunner<T>(
+                                segmentId, adapter.getDataInterval().getStart(),
+                                factory.createRunner(adapter)
+                            );
+                          }
+                        }
                     ),
                     factory.getToolchest()
                 )
diff --git a/processing/src/test/java/io/druid/query/timeseries/TimeSeriesUnionQueryRunnerTest.java b/processing/src/test/java/io/druid/query/timeseries/TimeSeriesUnionQueryRunnerTest.java
index 84ace0a798f..9a56a0208e4 100644
--- a/processing/src/test/java/io/druid/query/timeseries/TimeSeriesUnionQueryRunnerTest.java
+++ b/processing/src/test/java/io/druid/query/timeseries/TimeSeriesUnionQueryRunnerTest.java
@@ -19,7 +19,9 @@
 
 package io.druid.query.timeseries;
 
+import com.google.common.base.Function;
 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;
@@ -41,9 +43,11 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 
+import javax.annotation.Nullable;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
 
 @RunWith(Parameterized.class)
@@ -66,7 +70,8 @@ public class TimeSeriesUnionQueryRunnerTest
             new TimeseriesQueryQueryToolChest(new QueryConfig()),
             new TimeseriesQueryEngine(),
             QueryRunnerTestHelper.NOOP_QUERYWATCHER
-        )
+        ),
+        QueryRunnerTestHelper.unionDataSource
     );
   }
 
@@ -139,79 +144,86 @@ public class TimeSeriesUnionQueryRunnerTest
     QueryToolChest toolChest = new TimeseriesQueryQueryToolChest(new QueryConfig());
     QueryRunner mergingrunner = toolChest.mergeResults(
         new UnionQueryRunner<Result<TimeseriesResultValue>>(
-            new QueryRunner<Result<TimeseriesResultValue>>()
-            {
-              @Override
-              public Sequence<Result<TimeseriesResultValue>> run(Query<Result<TimeseriesResultValue>> query)
-              {
-                if (query.getDataSource().equals(new TableDataSource("ds1"))) {
-                  return Sequences.simple(
-                      Lists.newArrayList(
-                          new Result<TimeseriesResultValue>(
-                              new DateTime("2011-04-02"),
-                              new TimeseriesResultValue(
-                                  ImmutableMap.<String, Object>of(
-                                      "rows",
-                                      1L,
-                                      "idx",
-                                      2L
+            (Iterable)Arrays.asList(
+                new QueryRunner<Result<TimeseriesResultValue>>()
+                                    {
+                                      @Override
+                                      public Sequence<Result<TimeseriesResultValue>> run(Query<Result<TimeseriesResultValue>> query)
+                                      {
+                                          return Sequences.simple(
+                                              Lists.newArrayList(
+                                                  new Result<TimeseriesResultValue>(
+                                                      new DateTime("2011-04-02"),
+                                                      new TimeseriesResultValue(
+                                                          ImmutableMap.<String, Object>of(
+                                                              "rows",
+                                                              1L,
+                                                              "idx",
+                                                              2L
+                                                          )
+                                                      )
+                                                  ),
+                                                  new Result<TimeseriesResultValue>(
+                                                      new DateTime("2011-04-03"),
+                                                      new TimeseriesResultValue(
+                                                          ImmutableMap.<String, Object>of(
+                                                              "rows",
+                                                              3L,
+                                                              "idx",
+                                                              4L
+                                                          )
+                                                      )
+                                                  )
+                                              )
+                                          );
+                                      }
+                                    },
+                new QueryRunner<Result<TimeseriesResultValue>>(){
+
+                  @Override
+                  public Sequence<Result<TimeseriesResultValue>> run(Query<Result<TimeseriesResultValue>> query)
+                  {
+                    {
+                      return Sequences.simple(
+                          Lists.newArrayList(
+                              new Result<TimeseriesResultValue>(
+                                  new DateTime("2011-04-01"),
+                                  new TimeseriesResultValue(
+                                      ImmutableMap.<String, Object>of(
+                                          "rows",
+                                          5L,
+                                          "idx",
+                                          6L
+                                      )
                                   )
-                              )
-                          ),
-                          new Result<TimeseriesResultValue>(
-                              new DateTime("2011-04-03"),
-                              new TimeseriesResultValue(
-                                  ImmutableMap.<String, Object>of(
-                                      "rows",
-                                      3L,
-                                      "idx",
-                                      4L
+                              ),
+                              new Result<TimeseriesResultValue>(
+                                  new DateTime("2011-04-02"),
+                                  new TimeseriesResultValue(
+                                      ImmutableMap.<String, Object>of(
+                                          "rows",
+                                          7L,
+                                          "idx",
+                                          8L
+                                      )
+                                  )
+                              ),
+                              new Result<TimeseriesResultValue>(
+                                  new DateTime("2011-04-04"),
+                                  new TimeseriesResultValue(
+                                      ImmutableMap.<String, Object>of(
+                                          "rows",
+                                          9L,
+                                          "idx",
+                                          10L
+                                      )
                                   )
                               )
                           )
-                      )
-                  );
-                } else {
-                  return Sequences.simple(
-                      Lists.newArrayList(
-                          new Result<TimeseriesResultValue>(
-                              new DateTime("2011-04-01"),
-                              new TimeseriesResultValue(
-                                  ImmutableMap.<String, Object>of(
-                                      "rows",
-                                      5L,
-                                      "idx",
-                                      6L
-                                  )
-                              )
-                          ),
-                          new Result<TimeseriesResultValue>(
-                              new DateTime("2011-04-02"),
-                              new TimeseriesResultValue(
-                                  ImmutableMap.<String, Object>of(
-                                      "rows",
-                                      7L,
-                                      "idx",
-                                      8L
-                                  )
-                              )
-                          ),
-                          new Result<TimeseriesResultValue>(
-                              new DateTime("2011-04-04"),
-                              new TimeseriesResultValue(
-                                  ImmutableMap.<String, Object>of(
-                                      "rows",
-                                      9L,
-                                      "idx",
-                                      10L
-                                  )
-                              )
-                          )
-                      )
-                  );
-                }
-              }
-            },
+                      );
+                    }
+                  }
+                }),
             toolChest
         )
     );
diff --git a/processing/src/test/java/io/druid/query/topn/TopNUnionQueryTest.java b/processing/src/test/java/io/druid/query/topn/TopNUnionQueryTest.java
index 7dc7b645cad..5034fda9865 100644
--- a/processing/src/test/java/io/druid/query/topn/TopNUnionQueryTest.java
+++ b/processing/src/test/java/io/druid/query/topn/TopNUnionQueryTest.java
@@ -67,7 +67,8 @@ public class TopNUnionQueryTest
                 TestQueryRunners.getPool(),
                 new TopNQueryQueryToolChest(new TopNQueryConfig()),
                 QueryRunnerTestHelper.NOOP_QUERYWATCHER
-            )
+            ),
+            QueryRunnerTestHelper.unionDataSource
         )
     );
     retVal.addAll(
@@ -85,7 +86,8 @@ public class TopNUnionQueryTest
                 ),
                 new TopNQueryQueryToolChest(new TopNQueryConfig()),
                 QueryRunnerTestHelper.NOOP_QUERYWATCHER
-            )
+            ),
+            QueryRunnerTestHelper.unionDataSource
         )
     );
 
diff --git a/server/src/main/java/io/druid/client/BrokerServerView.java b/server/src/main/java/io/druid/client/BrokerServerView.java
index c0403c129e7..76b1207e508 100644
--- a/server/src/main/java/io/druid/client/BrokerServerView.java
+++ b/server/src/main/java/io/druid/client/BrokerServerView.java
@@ -20,6 +20,8 @@
 package io.druid.client;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.api.client.util.Lists;
+import com.google.common.base.Function;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Ordering;
@@ -37,10 +39,16 @@ import io.druid.query.QueryToolChestWarehouse;
 import io.druid.query.QueryWatcher;
 import io.druid.server.coordination.DruidServerMetadata;
 import io.druid.timeline.DataSegment;
+import io.druid.timeline.TimelineLookup;
+import io.druid.timeline.TimelineObjectHolder;
+import io.druid.timeline.UnionTimeLineLookup;
 import io.druid.timeline.VersionedIntervalTimeline;
 import io.druid.timeline.partition.PartitionChunk;
+import org.joda.time.Interval;
 
+import javax.annotation.Nullable;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.Executor;
@@ -245,11 +253,27 @@ public class BrokerServerView implements TimelineServerView
 
 
   @Override
-  public VersionedIntervalTimeline<String, ServerSelector> getTimeline(DataSource dataSource)
+  public TimelineLookup<String, ServerSelector> getTimeline(DataSource dataSource)
   {
-    String table = Iterables.getOnlyElement(dataSource.getNames());
+    final List<String> tables = dataSource.getNames();
     synchronized (lock) {
-      return timelines.get(table);
+      if (tables.size() == 1) {
+        return timelines.get(tables.get(0));
+      } else {
+        return new UnionTimeLineLookup<>(
+            Iterables.transform(
+                tables, new Function<String, TimelineLookup<String, ServerSelector>>()
+                {
+
+                  @Override
+                  public TimelineLookup<String, ServerSelector> apply(String input)
+                  {
+                    return timelines.get(input);
+                  }
+                }
+            )
+        );
+      }
     }
   }
 
diff --git a/server/src/main/java/io/druid/client/CachingClusteredClient.java b/server/src/main/java/io/druid/client/CachingClusteredClient.java
index f189e060670..087bc96927d 100644
--- a/server/src/main/java/io/druid/client/CachingClusteredClient.java
+++ b/server/src/main/java/io/druid/client/CachingClusteredClient.java
@@ -56,6 +56,7 @@ import io.druid.query.aggregation.MetricManipulatorFns;
 import io.druid.query.spec.MultipleSpecificSegmentSpec;
 import io.druid.server.coordination.DruidServerMetadata;
 import io.druid.timeline.DataSegment;
+import io.druid.timeline.TimelineLookup;
 import io.druid.timeline.TimelineObjectHolder;
 import io.druid.timeline.VersionedIntervalTimeline;
 import io.druid.timeline.partition.PartitionChunk;
@@ -149,7 +150,7 @@ public class CachingClusteredClient<T> implements QueryRunner<T>
     final Query<T> rewrittenQuery = query.withOverriddenContext(contextBuilder.build());
 
 
-    VersionedIntervalTimeline<String, ServerSelector> timeline = serverView.getTimeline(query.getDataSource());
+    TimelineLookup<String, ServerSelector> timeline = serverView.getTimeline(query.getDataSource());
     if (timeline == null) {
       return Sequences.empty();
     }
diff --git a/server/src/main/java/io/druid/client/TimelineServerView.java b/server/src/main/java/io/druid/client/TimelineServerView.java
index 0a6a43c8fdb..b3cc8cf6832 100644
--- a/server/src/main/java/io/druid/client/TimelineServerView.java
+++ b/server/src/main/java/io/druid/client/TimelineServerView.java
@@ -22,12 +22,13 @@ package io.druid.client;
 import io.druid.client.selector.ServerSelector;
 import io.druid.query.DataSource;
 import io.druid.query.QueryRunner;
+import io.druid.timeline.TimelineLookup;
 import io.druid.timeline.VersionedIntervalTimeline;
 
 /**
  */
 public interface TimelineServerView extends ServerView
 {
-  VersionedIntervalTimeline<String, ServerSelector> getTimeline(DataSource dataSource);
+  TimelineLookup<String, ServerSelector> getTimeline(DataSource dataSource);
   <T> QueryRunner<T> getQueryRunner(DruidServer server);
 }
diff --git a/server/src/main/java/io/druid/segment/realtime/RealtimeManager.java b/server/src/main/java/io/druid/segment/realtime/RealtimeManager.java
index a1cfb220972..3998c7503b1 100644
--- a/server/src/main/java/io/druid/segment/realtime/RealtimeManager.java
+++ b/server/src/main/java/io/druid/segment/realtime/RealtimeManager.java
@@ -19,6 +19,7 @@
 
 package io.druid.segment.realtime;
 
+import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
 import com.google.common.collect.Iterables;
@@ -40,6 +41,7 @@ import io.druid.query.QueryRunnerFactoryConglomerate;
 import io.druid.query.QuerySegmentWalker;
 import io.druid.query.QueryToolChest;
 import io.druid.query.SegmentDescriptor;
+import io.druid.query.UnionQueryRunner;
 import io.druid.segment.indexing.DataSchema;
 import io.druid.segment.indexing.RealtimeTuningConfig;
 import io.druid.segment.realtime.plumber.Plumber;
@@ -47,6 +49,7 @@ import org.joda.time.DateTime;
 import org.joda.time.Interval;
 import org.joda.time.Period;
 
+import javax.annotation.Nullable;
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.List;
@@ -117,11 +120,28 @@ public class RealtimeManager implements QuerySegmentWalker
   }
 
   @Override
-  public <T> QueryRunner<T> getQueryRunnerForSegments(Query<T> query, Iterable<SegmentDescriptor> specs)
+  public <T> QueryRunner<T> getQueryRunnerForSegments(final Query<T> query, Iterable<SegmentDescriptor> specs)
   {
-    final FireChief chief = chiefs.get(getDataSourceName(query));
-
-    return chief == null ? new NoopQueryRunner<T>() : chief.getQueryRunner(query);
+    final List<String> names = query.getDataSource().getNames();
+    if (names.size() == 1) {
+      final FireChief chief = chiefs.get(names.get(0));
+      return chief == null ? new NoopQueryRunner<T>() : chief.getQueryRunner(query);
+    } else {
+      return new UnionQueryRunner<>(
+          Iterables.transform(
+              names, new Function<String, QueryRunner<T>>()
+              {
+                @Nullable
+                @Override
+                public QueryRunner<T> apply(@Nullable String input)
+                {
+                  final FireChief chief = chiefs.get(input);
+                  return chief == null ? new NoopQueryRunner<T>() : chief.getQueryRunner(query);
+                }
+              }
+          ), conglomerate.findFactory(query).getToolchest()
+      );
+    }
   }
 
   private <T> String getDataSourceName(Query<T> query)
diff --git a/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java b/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java
index 311f0162c5a..c81fa618b2f 100644
--- a/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java
+++ b/server/src/main/java/io/druid/server/ClientQuerySegmentWalker.java
@@ -82,7 +82,6 @@ public class ClientQuerySegmentWalker implements QuerySegmentWalker
     final FinalizeResultsQueryRunner<T> baseRunner = new FinalizeResultsQueryRunner<T>(
         toolChest.postMergeQueryDecoration(
             toolChest.mergeResults(
-                new UnionQueryRunner<T>(
                     new MetricsEmittingQueryRunner<T>(
                         emitter,
                         new Function<Query<T>, ServiceMetricEvent.Builder>()
@@ -94,9 +93,7 @@ public class ClientQuerySegmentWalker implements QuerySegmentWalker
                           }
                         },
                         toolChest.preMergeQueryDecoration(baseClient)
-                    ).withWaitMeasuredFromNow(),
-                    toolChest
-                )
+                    ).withWaitMeasuredFromNow()
             )
         ),
         toolChest
diff --git a/server/src/main/java/io/druid/server/coordination/ServerManager.java b/server/src/main/java/io/druid/server/coordination/ServerManager.java
index e79e4a3a978..e5445774e0a 100644
--- a/server/src/main/java/io/druid/server/coordination/ServerManager.java
+++ b/server/src/main/java/io/druid/server/coordination/ServerManager.java
@@ -33,6 +33,7 @@ import com.metamx.emitter.service.ServiceMetricEvent;
 import io.druid.client.CachingQueryRunner;
 import io.druid.client.cache.Cache;
 import io.druid.client.cache.CacheConfig;
+import io.druid.client.selector.ServerSelector;
 import io.druid.collections.CountingMap;
 import io.druid.guice.annotations.Processing;
 import io.druid.guice.annotations.Smile;
@@ -42,6 +43,7 @@ import io.druid.query.FinalizeResultsQueryRunner;
 import io.druid.query.MetricsEmittingQueryRunner;
 import io.druid.query.NoopQueryRunner;
 import io.druid.query.Query;
+import io.druid.query.QueryDataSource;
 import io.druid.query.QueryRunner;
 import io.druid.query.QueryRunnerFactory;
 import io.druid.query.QueryRunnerFactoryConglomerate;
@@ -57,7 +59,9 @@ import io.druid.segment.Segment;
 import io.druid.segment.loading.SegmentLoader;
 import io.druid.segment.loading.SegmentLoadingException;
 import io.druid.timeline.DataSegment;
+import io.druid.timeline.TimelineLookup;
 import io.druid.timeline.TimelineObjectHolder;
+import io.druid.timeline.UnionTimeLineLookup;
 import io.druid.timeline.VersionedIntervalTimeline;
 import io.druid.timeline.partition.PartitionChunk;
 import io.druid.timeline.partition.PartitionHolder;
@@ -67,6 +71,7 @@ import javax.annotation.Nullable;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 
@@ -163,7 +168,7 @@ public class ServerManager implements QuerySegmentWalker
       VersionedIntervalTimeline<String, ReferenceCountingSegment> loadedIntervals = dataSources.get(dataSource);
 
       if (loadedIntervals == null) {
-        loadedIntervals = new VersionedIntervalTimeline<String, ReferenceCountingSegment>(Ordering.natural());
+        loadedIntervals = new VersionedIntervalTimeline<>(Ordering.natural());
         dataSources.put(dataSource, loadedIntervals);
       }
 
@@ -250,12 +255,11 @@ public class ServerManager implements QuerySegmentWalker
     final QueryToolChest<T, Query<T>> toolChest = factory.getToolchest();
 
     DataSource dataSource = query.getDataSource();
-    if (!(dataSource instanceof TableDataSource)) {
+    if (dataSource instanceof QueryDataSource) {
       throw new UnsupportedOperationException("data source type '" + dataSource.getClass().getName() + "' unsupported");
     }
-    String dataSourceName = getDataSourceName(dataSource);
 
-    final VersionedIntervalTimeline<String, ReferenceCountingSegment> timeline = dataSources.get(dataSourceName);
+    final TimelineLookup<String, ReferenceCountingSegment> timeline = getTimelineLookup(query.getDataSource());
 
     if (timeline == null) {
       return new NoopQueryRunner<T>();
@@ -302,7 +306,6 @@ public class ServerManager implements QuerySegmentWalker
                                     holder.getVersion(),
                                     input.getChunkNumber()
                                 )
-
                             );
                           }
                         }
@@ -319,9 +322,26 @@ public class ServerManager implements QuerySegmentWalker
     return new FinalizeResultsQueryRunner<T>(toolChest.mergeResults(factory.mergeRunners(exec, adapters)), toolChest);
   }
 
-  private String getDataSourceName(DataSource dataSource)
+  private TimelineLookup<String, ReferenceCountingSegment> getTimelineLookup(DataSource dataSource)
   {
-    return Iterables.getOnlyElement(dataSource.getNames());
+    final List<String> names = dataSource.getNames();
+    if(names.size() == 1){
+      return dataSources.get(names.get(0));
+    } else {
+      return new UnionTimeLineLookup<>(
+          Iterables.transform(
+              names, new Function<String, TimelineLookup<String, ReferenceCountingSegment>>()
+              {
+
+                @Override
+                public TimelineLookup<String, ReferenceCountingSegment> apply(String input)
+                {
+                  return dataSources.get(input);
+                }
+              }
+          )
+      );
+    }
   }
 
   @Override
@@ -337,9 +357,7 @@ public class ServerManager implements QuerySegmentWalker
 
     final QueryToolChest<T, Query<T>> toolChest = factory.getToolchest();
 
-    String dataSourceName = getDataSourceName(query.getDataSource());
-
-    final VersionedIntervalTimeline<String, ReferenceCountingSegment> timeline = dataSources.get(dataSourceName);
+    final TimelineLookup<String, ReferenceCountingSegment> timeline = getTimelineLookup(query.getDataSource());
 
     if (timeline == null) {
       return new NoopQueryRunner<T>();
@@ -354,6 +372,7 @@ public class ServerManager implements QuerySegmentWalker
               @SuppressWarnings("unchecked")
               public Iterable<QueryRunner<T>> apply(SegmentDescriptor input)
               {
+
                 final PartitionHolder<ReferenceCountingSegment> entry = timeline.findEntry(
                     input.getInterval(), input.getVersion()
                 );