Merge branch 'master' of github.com:metamx/druid

docs/content/Broker-Config.md

@@ -81,7 +81,7 @@ druid.server.http.numThreads=50
 druid.request.logging.type=emitter
 druid.request.logging.feed=druid_requests
 
-druid.monitoring.monitors=["com.metamx.metrics.SysMonitor","com.metamx.metrics.JvmMonitor", "io.druid.client.cache.CacheMonitor"]
+druid.monitoring.monitors=["com.metamx.metrics.SysMonitor","com.metamx.metrics.JvmMonitor"]
 
 # Emit metrics over http
 druid.emitter=http
@@ -106,16 +106,16 @@ The broker module uses several of the default modules in [Configuration](Configu
 
 |Property|Description|Default|
 |--------|-----------|-------|
-|`druid.broker.cache.sizeInBytes`|Maximum size of the cache. If this is zero, cache is disabled.|10485760 (10MB)|
+|`druid.broker.cache.sizeInBytes`|Maximum cache size in bytes. Zero disables caching.|0|
-|`druid.broker.cache.initialSize`|The initial size of the cache in bytes.|500000|
+|`druid.broker.cache.initialSize`|Initial size of the hashtable backing the cache.|500000|
-|`druid.broker.cache.logEvictionCount`|If this is non-zero, there will be an eviction of entries.|0|
+|`druid.broker.cache.logEvictionCount`|If non-zero, log cache eviction every `logEvictionCount` items.|0|
 
 #### Memcache
 
 |Property|Description|Default|
 |--------|-----------|-------|
-|`druid.broker.cache.expiration`|Memcache [expiration time ](https://code.google.com/p/memcached/wiki/NewCommands#Standard_Protocol).|2592000 (30 days)|
+|`druid.broker.cache.expiration`|Memcached [expiration time](https://code.google.com/p/memcached/wiki/NewCommands#Standard_Protocol).|2592000 (30 days)|
-|`druid.broker.cache.timeout`|Maximum time in milliseconds to wait for a response from Memcache.|500|
+|`druid.broker.cache.timeout`|Maximum time in milliseconds to wait for a response from Memcached.|500|
-|`druid.broker.cache.hosts`|Memcache hosts.|none|
+|`druid.broker.cache.hosts`|Command separated list of Memcached hosts `<host:port>`.|none|
-|`druid.broker.cache.maxObjectSize`|Maximum object size in bytes for a Memcache object.|52428800 (50 MB)|
+|`druid.broker.cache.maxObjectSize`|Maximum object size in bytes for a Memcached object.|52428800 (50 MB)|
-|`druid.broker.cache.memcachedPrefix`|Key prefix for all keys in Memcache.|druid|
+|`druid.broker.cache.memcachedPrefix`|Key prefix for all keys in Memcached.|druid|

pom.xml

@@ -313,17 +313,17 @@
             <dependency>
                 <groupId>org.eclipse.jetty</groupId>
                 <artifactId>jetty-server</artifactId>
-                <version>9.1.3.v20140225</version>
+                <version>9.1.4.v20140401</version>
             </dependency>
             <dependency>
                 <groupId>org.eclipse.jetty</groupId>
                 <artifactId>jetty-servlet</artifactId>
-                <version>9.1.3.v20140225</version>
+                <version>9.1.4.v20140401</version>
             </dependency>
             <dependency>
                 <groupId>org.eclipse.jetty</groupId>
                 <artifactId>jetty-servlets</artifactId>
-                <version>9.1.3.v20140225</version>
+                <version>9.1.4.v20140401</version>
             </dependency>
             <dependency>
                 <groupId>joda-time</groupId>

processing/src/main/java/io/druid/query/aggregation/AggregatorUtil.java

@@ -0,0 +1,56 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013, 2014  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.query.aggregation;
+
+import com.google.common.collect.Lists;
+
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+
+public class AggregatorUtil
+{
+  /**
+   * returns the list of dependent postAggregators that should be calculated in order to calculate given postAgg
+   *
+   * @param postAggregatorList List of postAggregator, there is a restriction that the list should be in an order
+   *                           such that all the dependencies of any given aggregator should occur before that aggregator.
+   *                           See AggregatorUtilTest.testOutOfOrderPruneDependentPostAgg for example.
+   * @param postAggName        name of the postAgg on which dependency is to be calculated
+   */
+  public static List<PostAggregator> pruneDependentPostAgg(List<PostAggregator> postAggregatorList, String postAggName)
+  {
+    LinkedList<PostAggregator> rv = Lists.newLinkedList();
+    Set<String> deps = new HashSet<>();
+    deps.add(postAggName);
+    // Iterate backwards to find the last calculated aggregate and add dependent aggregator as we find dependencies in reverse order
+    for (PostAggregator agg : Lists.reverse(postAggregatorList)) {
+      if (deps.contains(agg.getName())) {
+        rv.addFirst(agg); // add to the beginning of List
+        deps.remove(agg.getName());
+        deps.addAll(agg.getDependentFields());
+      }
+    }
+
+    return rv;
+  }
+
+}

processing/src/main/java/io/druid/query/timeseries/TimeseriesBinaryFn.java

@@ -24,7 +24,6 @@ import io.druid.granularity.AllGranularity;
 import io.druid.granularity.QueryGranularity;
 import io.druid.query.Result;
 import io.druid.query.aggregation.AggregatorFactory;
-import io.druid.query.aggregation.PostAggregator;
 
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -37,17 +36,14 @@ public class TimeseriesBinaryFn
 {
   private final QueryGranularity gran;
   private final List<AggregatorFactory> aggregations;
-  private final List<PostAggregator> postAggregations;
 
   public TimeseriesBinaryFn(
       QueryGranularity granularity,
-      List<AggregatorFactory> aggregations,
+      List<AggregatorFactory> aggregations
-      List<PostAggregator> postAggregations
   )
   {
     this.gran = granularity;
     this.aggregations = aggregations;
-    this.postAggregations = postAggregations;
   }
 
   @Override
@@ -71,11 +67,6 @@ public class TimeseriesBinaryFn
       retVal.put(metricName, factory.combine(arg1Val.getMetric(metricName), arg2Val.getMetric(metricName)));
     }
 
-    for (PostAggregator pf : postAggregations) {
-      final String metricName = pf.getName();
-      retVal.put(metricName, pf.compute(retVal));
-    }
-
     return (gran instanceof AllGranularity) ?
            new Result<TimeseriesResultValue>(
                arg1.getTimestamp(),

processing/src/main/java/io/druid/query/timeseries/TimeseriesQueryEngine.java

@@ -74,10 +74,6 @@ public class TimeseriesQueryEngine
                       bob.addMetric(aggregator);
                     }
 
-                    for (PostAggregator postAgg : postAggregatorSpecs) {
-                      bob.addMetric(postAgg);
-                    }
-
                     Result<TimeseriesResultValue> retVal = bob.build();
 
                     // cleanup

processing/src/main/java/io/druid/query/timeseries/TimeseriesQueryQueryToolChest.java

@@ -101,8 +101,7 @@ public class TimeseriesQueryQueryToolChest extends QueryToolChest<Result<Timeser
         TimeseriesQuery query = (TimeseriesQuery) input;
         return new TimeseriesBinaryFn(
             query.getGranularity(),
-            query.getAggregatorSpecs(),
+            query.getAggregatorSpecs()
-            query.getPostAggregatorSpecs()
         );
       }
     };
@@ -147,7 +146,7 @@ public class TimeseriesQueryQueryToolChest extends QueryToolChest<Result<Timeser
           values.put(agg.getName(), fn.manipulate(agg, holder.getMetric(agg.getName())));
         }
         for (PostAggregator postAgg : query.getPostAggregatorSpecs()) {
-          values.put(postAgg.getName(), holder.getMetric(postAgg.getName()));
+            values.put(postAgg.getName(), postAgg.compute(values));
         }
         return new Result<TimeseriesResultValue>(
             result.getTimestamp(),
@@ -169,7 +168,6 @@ public class TimeseriesQueryQueryToolChest extends QueryToolChest<Result<Timeser
     return new CacheStrategy<Result<TimeseriesResultValue>, Object, TimeseriesQuery>()
     {
       private final List<AggregatorFactory> aggs = query.getAggregatorSpecs();
-      private final List<PostAggregator> postAggs = query.getPostAggregatorSpecs();
 
       @Override
       public byte[] computeCacheKey(TimeseriesQuery query)
@@ -238,10 +236,6 @@ public class TimeseriesQueryQueryToolChest extends QueryToolChest<Result<Timeser
               retVal.put(factory.getName(), factory.deserialize(resultIter.next()));
             }
 
-            for (PostAggregator postAgg : postAggs) {
-              retVal.put(postAgg.getName(), postAgg.compute(retVal));
-            }
-
             return new Result<TimeseriesResultValue>(
                 timestamp,
                 new TimeseriesResultValue(retVal)

processing/src/main/java/io/druid/query/topn/AggregateTopNMetricFirstAlgorithm.java

@@ -56,7 +56,6 @@ public class AggregateTopNMetricFirstAlgorithm implements TopNAlgorithm<int[], T
     this.bufferPool = bufferPool;
   }
 
-
   @Override
   public TopNParams makeInitParams(
       DimensionSelector dimSelector, Cursor cursor
@@ -69,7 +68,12 @@ public class AggregateTopNMetricFirstAlgorithm implements TopNAlgorithm<int[], T
   public TopNResultBuilder makeResultBuilder(TopNParams params)
   {
     return query.getTopNMetricSpec().getResultBuilder(
-        params.getCursor().getTime(), query.getDimensionSpec(), query.getThreshold(), comparator
+        params.getCursor().getTime(),
+        query.getDimensionSpec(),
+        query.getThreshold(),
+        comparator,
+        query.getAggregatorSpecs(),
+        query.getPostAggregatorSpecs()
     );
   }
 

processing/src/main/java/io/druid/query/topn/DimExtractionTopNAlgorithm.java

@@ -60,7 +60,12 @@ public class DimExtractionTopNAlgorithm extends BaseTopNAlgorithm<Aggregator[][]
   public TopNResultBuilder makeResultBuilder(TopNParams params)
   {
     return query.getTopNMetricSpec().getResultBuilder(
-        params.getCursor().getTime(), query.getDimensionSpec(), query.getThreshold(), comparator
+        params.getCursor().getTime(),
+        query.getDimensionSpec(),
+        query.getThreshold(),
+        comparator,
+        query.getAggregatorSpecs(),
+        query.getPostAggregatorSpecs()
     );
   }
 
@@ -144,9 +149,7 @@ public class DimExtractionTopNAlgorithm extends BaseTopNAlgorithm<Aggregator[][]
         resultBuilder.addEntry(
             entry.getKey(),
             entry.getKey(),
-            vals,
+            vals
-            query.getAggregatorSpecs(),
-            query.getPostAggregatorSpecs()
         );
       }
     }

processing/src/main/java/io/druid/query/topn/InvertedTopNMetricSpec.java

@@ -36,7 +36,6 @@ import java.util.List;
 public class InvertedTopNMetricSpec implements TopNMetricSpec
 {
   private static final byte CACHE_TYPE_ID = 0x3;
-
   private final TopNMetricSpec delegate;
 
   @JsonCreator
@@ -76,10 +75,12 @@ public class InvertedTopNMetricSpec implements TopNMetricSpec
       DateTime timestamp,
       DimensionSpec dimSpec,
       int threshold,
-      Comparator comparator
+      Comparator comparator,
+      List<AggregatorFactory> aggFactories,
+      List<PostAggregator> postAggs
   )
   {
-    return delegate.getResultBuilder(timestamp, dimSpec, threshold, comparator);
+    return delegate.getResultBuilder(timestamp, dimSpec, threshold, comparator, aggFactories, postAggs);
   }
 
   @Override
@@ -102,15 +103,27 @@ public class InvertedTopNMetricSpec implements TopNMetricSpec
     delegate.initTopNAlgorithmSelector(selector);
   }
 
+  @Override
+  public String getMetricName(DimensionSpec dimSpec)
+  {
+    return delegate.getMetricName(dimSpec);
+  }
+
   @Override
   public boolean equals(Object o)
   {
-    if (this == o) return true;
+    if (this == o) {
-    if (o == null || getClass() != o.getClass()) return false;
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
 
     InvertedTopNMetricSpec that = (InvertedTopNMetricSpec) o;
 
-    if (delegate != null ? !delegate.equals(that.delegate) : that.delegate != null) return false;
+    if (delegate != null ? !delegate.equals(that.delegate) : that.delegate != null) {
+      return false;
+    }
 
     return true;
   }

processing/src/main/java/io/druid/query/topn/LexicographicTopNMetricSpec.java

@@ -80,10 +80,12 @@ public class LexicographicTopNMetricSpec implements TopNMetricSpec
       DateTime timestamp,
       DimensionSpec dimSpec,
       int threshold,
-      Comparator comparator
+      Comparator comparator,
+      List<AggregatorFactory> aggFactories,
+      List<PostAggregator> postAggs
   )
   {
-    return new TopNLexicographicResultBuilder(timestamp, dimSpec, threshold, previousStop, comparator);
+    return new TopNLexicographicResultBuilder(timestamp, dimSpec, threshold, previousStop, comparator, aggFactories);
   }
 
   @Override
@@ -111,6 +113,12 @@ public class LexicographicTopNMetricSpec implements TopNMetricSpec
     selector.setAggregateAllMetrics(true);
   }
 
+  @Override
+  public String getMetricName(DimensionSpec dimSpec)
+  {
+    return dimSpec.getOutputName();
+  }
+
   @Override
   public String toString()
   {

processing/src/main/java/io/druid/query/topn/NumericTopNMetricSpec.java

@@ -121,10 +121,12 @@ public class NumericTopNMetricSpec implements TopNMetricSpec
       DateTime timestamp,
       DimensionSpec dimSpec,
       int threshold,
-      Comparator comparator
+      Comparator comparator,
+      List<AggregatorFactory> aggFactories,
+      List<PostAggregator> postAggs
   )
   {
-    return new TopNNumericResultBuilder(timestamp, dimSpec, metric, threshold, comparator);
+    return new TopNNumericResultBuilder(timestamp, dimSpec, metric, threshold, comparator, aggFactories, postAggs);
   }
 
   @Override
@@ -150,6 +152,12 @@ public class NumericTopNMetricSpec implements TopNMetricSpec
     selector.setAggregateTopNMetricFirst(true);
   }
 
+  @Override
+  public String getMetricName(DimensionSpec dimSpec)
+  {
+    return metric;
+  }
+
   @Override
   public String toString()
   {

processing/src/main/java/io/druid/query/topn/PooledTopNAlgorithm.java

@@ -35,7 +35,8 @@ import java.util.Comparator;
 
 /**
  */
-public class PooledTopNAlgorithm extends BaseTopNAlgorithm<int[], BufferAggregator[], PooledTopNAlgorithm.PooledTopNParams>
+public class PooledTopNAlgorithm
+    extends BaseTopNAlgorithm<int[], BufferAggregator[], PooledTopNAlgorithm.PooledTopNParams>
 {
   private final Capabilities capabilities;
   private final TopNQuery query;
@@ -117,7 +118,12 @@ public class PooledTopNAlgorithm extends BaseTopNAlgorithm<int[], BufferAggregat
   public TopNResultBuilder makeResultBuilder(PooledTopNParams params)
   {
     return query.getTopNMetricSpec().getResultBuilder(
-        params.getCursor().getTime(), query.getDimensionSpec(), query.getThreshold(), comparator
+        params.getCursor().getTime(),
+        query.getDimensionSpec(),
+        query.getThreshold(),
+        comparator,
+        query.getAggregatorSpecs(),
+        query.getPostAggregatorSpecs()
     );
   }
 
@@ -217,9 +223,7 @@ public class PooledTopNAlgorithm extends BaseTopNAlgorithm<int[], BufferAggregat
         resultBuilder.addEntry(
             dimSelector.lookupName(i),
             i,
-            vals,
+            vals
-            query.getAggregatorSpecs(),
-            query.getPostAggregatorSpecs()
         );
       }
     }
@@ -228,7 +232,7 @@ public class PooledTopNAlgorithm extends BaseTopNAlgorithm<int[], BufferAggregat
   @Override
   protected void closeAggregators(BufferAggregator[] bufferAggregators)
   {
-    for(BufferAggregator agg : bufferAggregators) {
+    for (BufferAggregator agg : bufferAggregators) {
       agg.close();
     }
   }
@@ -246,11 +250,6 @@ public class PooledTopNAlgorithm extends BaseTopNAlgorithm<int[], BufferAggregat
 
   public static class PooledTopNParams extends TopNParams
   {
-    public static Builder builder()
-    {
-      return new Builder();
-    }
-
     private final ResourceHolder<ByteBuffer> resultsBufHolder;
     private final ByteBuffer resultsBuf;
     private final int[] aggregatorSizes;
@@ -278,6 +277,11 @@ public class PooledTopNAlgorithm extends BaseTopNAlgorithm<int[], BufferAggregat
       this.arrayProvider = arrayProvider;
     }
 
+    public static Builder builder()
+    {
+      return new Builder();
+    }
+
     public ResourceHolder<ByteBuffer> getResultsBufHolder()
     {
       return resultsBufHolder;

processing/src/main/java/io/druid/query/topn/TopNBinaryFn.java

@@ -24,6 +24,7 @@ import io.druid.granularity.AllGranularity;
 import io.druid.granularity.QueryGranularity;
 import io.druid.query.Result;
 import io.druid.query.aggregation.AggregatorFactory;
+import io.druid.query.aggregation.AggregatorUtil;
 import io.druid.query.aggregation.PostAggregator;
 import io.druid.query.dimension.DimensionSpec;
 import org.joda.time.DateTime;
@@ -40,7 +41,7 @@ public class TopNBinaryFn implements BinaryFn<Result<TopNResultValue>, Result<To
   private final TopNResultMerger merger;
   private final DimensionSpec dimSpec;
   private final QueryGranularity gran;
-  private final String dimension;
+  private final DimensionSpec dimensionSpec;
   private final TopNMetricSpec topNMetricSpec;
   private final int threshold;
   private final List<AggregatorFactory> aggregations;
@@ -63,9 +64,13 @@ public class TopNBinaryFn implements BinaryFn<Result<TopNResultValue>, Result<To
     this.topNMetricSpec = topNMetricSpec;
     this.threshold = threshold;
     this.aggregations = aggregatorSpecs;
-    this.postAggregations = postAggregatorSpecs;
+    this.dimensionSpec = dimSpec;
+
+    this.postAggregations = AggregatorUtil.pruneDependentPostAgg(
+        postAggregatorSpecs,
+        this.topNMetricSpec.getMetricName(this.dimensionSpec)
+    );
 
-    this.dimension = dimSpec.getOutputName();
     this.comparator = topNMetricSpec.getComparator(aggregatorSpecs, postAggregatorSpecs);
   }
 
@@ -79,11 +84,13 @@ public class TopNBinaryFn implements BinaryFn<Result<TopNResultValue>, Result<To
       return merger.getResult(arg1, comparator);
     }
 
-    Map<String, DimensionAndMetricValueExtractor> retVals = new LinkedHashMap<String, DimensionAndMetricValueExtractor>();
 
     TopNResultValue arg1Vals = arg1.getValue();
     TopNResultValue arg2Vals = arg2.getValue();
+    Map<String, DimensionAndMetricValueExtractor> retVals = new LinkedHashMap<String, DimensionAndMetricValueExtractor>();
 
+    String dimension = dimensionSpec.getOutputName();
+    String topNMetricName = topNMetricSpec.getMetricName(dimensionSpec);
     for (DimensionAndMetricValueExtractor arg1Val : arg1Vals) {
       retVals.put(arg1Val.getStringDimensionValue(dimension), arg1Val);
     }
@@ -92,16 +99,16 @@ public class TopNBinaryFn implements BinaryFn<Result<TopNResultValue>, Result<To
       DimensionAndMetricValueExtractor arg1Val = retVals.get(dimensionValue);
 
       if (arg1Val != null) {
-        Map<String, Object> retVal = new LinkedHashMap<String, Object>();
+        // size of map = aggregator + topNDim + postAgg (If sorting is done on post agg field)
+        Map<String, Object> retVal = new LinkedHashMap<String, Object>(aggregations.size() + 2);
 
         retVal.put(dimension, dimensionValue);
         for (AggregatorFactory factory : aggregations) {
           final String metricName = factory.getName();
           retVal.put(metricName, factory.combine(arg1Val.getMetric(metricName), arg2Val.getMetric(metricName)));
         }
-
+        for (PostAggregator postAgg : postAggregations) {
-        for (PostAggregator pf : postAggregations) {
+          retVal.put(postAgg.getName(), postAgg.compute(retVal));
-          retVal.put(pf.getName(), pf.compute(retVal));
         }
 
         retVals.put(dimensionValue, new DimensionAndMetricValueExtractor(retVal));
@@ -117,7 +124,14 @@ public class TopNBinaryFn implements BinaryFn<Result<TopNResultValue>, Result<To
       timestamp = gran.toDateTime(gran.truncate(arg1.getTimestamp().getMillis()));
     }
 
-    TopNResultBuilder bob = topNMetricSpec.getResultBuilder(timestamp, dimSpec, threshold, comparator);
+    TopNResultBuilder bob = topNMetricSpec.getResultBuilder(
+        timestamp,
+        dimSpec,
+        threshold,
+        comparator,
+        aggregations,
+        postAggregations
+    );
     for (DimensionAndMetricValueExtractor extractor : retVals.values()) {
       bob.addEntry(extractor);
     }

processing/src/main/java/io/druid/query/topn/TopNLexicographicResultBuilder.java

@@ -40,7 +40,7 @@ public class TopNLexicographicResultBuilder implements TopNResultBuilder
   private final DateTime timestamp;
   private final DimensionSpec dimSpec;
   private final String previousStop;
-
+  private final List<AggregatorFactory> aggFactories;
   private MinMaxPriorityQueue<DimValHolder> pQueue = null;
 
   public TopNLexicographicResultBuilder(
@@ -48,12 +48,14 @@ public class TopNLexicographicResultBuilder implements TopNResultBuilder
       DimensionSpec dimSpec,
       int threshold,
       String previousStop,
-      final Comparator comparator
+      final Comparator comparator,
+      List<AggregatorFactory> aggFactories
   )
   {
     this.timestamp = timestamp;
     this.dimSpec = dimSpec;
     this.previousStop = previousStop;
+    this.aggFactories = aggFactories;
 
     instantiatePQueue(threshold, comparator);
   }
@@ -62,9 +64,7 @@ public class TopNLexicographicResultBuilder implements TopNResultBuilder
   public TopNResultBuilder addEntry(
       String dimName,
       Object dimValIndex,
-      Object[] metricVals,
+      Object[] metricVals
-      List<AggregatorFactory> aggFactories,
-      List<PostAggregator> postAggs
   )
   {
     Map<String, Object> metricValues = Maps.newLinkedHashMap();
@@ -75,9 +75,6 @@ public class TopNLexicographicResultBuilder implements TopNResultBuilder
       for (Object metricVal : metricVals) {
         metricValues.put(aggsIter.next().getName(), metricVal);
       }
-      for (PostAggregator postAgg : postAggs) {
-        metricValues.put(postAgg.getName(), postAgg.compute(metricValues));
-      }
 
       pQueue.add(new DimValHolder.Builder().withDirName(dimName).withMetricValues(metricValues).build());
     }

processing/src/main/java/io/druid/query/topn/TopNMetricSpec.java

@@ -47,7 +47,9 @@ public interface TopNMetricSpec
       DateTime timestamp,
       DimensionSpec dimSpec,
       int threshold,
-      Comparator comparator
+      Comparator comparator,
+      List<AggregatorFactory> aggFactories,
+      List<PostAggregator> postAggs
   );
 
   public byte[] getCacheKey();
@@ -55,4 +57,6 @@ public interface TopNMetricSpec
   public <T> TopNMetricSpecBuilder<T> configureOptimizer(TopNMetricSpecBuilder<T> builder);
 
   public void initTopNAlgorithmSelector(TopNAlgorithmSelector selector);
+
+  public String getMetricName(DimensionSpec dimSpec);
 }

processing/src/main/java/io/druid/query/topn/TopNNumericResultBuilder.java

@@ -23,6 +23,7 @@ import com.google.common.collect.Maps;
 import com.google.common.collect.MinMaxPriorityQueue;
 import io.druid.query.Result;
 import io.druid.query.aggregation.AggregatorFactory;
+import io.druid.query.aggregation.AggregatorUtil;
 import io.druid.query.aggregation.PostAggregator;
 import io.druid.query.dimension.DimensionSpec;
 import org.joda.time.DateTime;
@@ -40,7 +41,8 @@ public class TopNNumericResultBuilder implements TopNResultBuilder
   private final DateTime timestamp;
   private final DimensionSpec dimSpec;
   private final String metricName;
-
+  private final List<AggregatorFactory> aggFactories;
+  private final List<PostAggregator> postAggs;
   private MinMaxPriorityQueue<DimValHolder> pQueue = null;
 
   public TopNNumericResultBuilder(
@@ -48,12 +50,16 @@ public class TopNNumericResultBuilder implements TopNResultBuilder
       DimensionSpec dimSpec,
       String metricName,
       int threshold,
-      final Comparator comparator
+      final Comparator comparator,
+      List<AggregatorFactory> aggFactories,
+      List<PostAggregator> postAggs
   )
   {
     this.timestamp = timestamp;
     this.dimSpec = dimSpec;
     this.metricName = metricName;
+    this.aggFactories = aggFactories;
+    this.postAggs = AggregatorUtil.pruneDependentPostAgg(postAggs, this.metricName);
 
     instantiatePQueue(threshold, comparator);
   }
@@ -62,9 +68,7 @@ public class TopNNumericResultBuilder implements TopNResultBuilder
   public TopNResultBuilder addEntry(
       String dimName,
       Object dimValIndex,
-      Object[] metricVals,
+      Object[] metricVals
-      List<AggregatorFactory> aggFactories,
-      List<PostAggregator> postAggs
   )
   {
     Map<String, Object> metricValues = Maps.newLinkedHashMap();
@@ -75,6 +79,7 @@ public class TopNNumericResultBuilder implements TopNResultBuilder
     for (Object metricVal : metricVals) {
       metricValues.put(aggFactoryIter.next().getName(), metricVal);
     }
+
     for (PostAggregator postAgg : postAggs) {
       metricValues.put(postAgg.getName(), postAgg.compute(metricValues));
     }

processing/src/main/java/io/druid/query/topn/TopNQueryQueryToolChest.java

@@ -64,11 +64,13 @@ import java.util.Map;
 public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultValue>, TopNQuery>
 {
   private static final byte TOPN_QUERY = 0x1;
-
   private static final Joiner COMMA_JOIN = Joiner.on(",");
-  private static final TypeReference<Result<TopNResultValue>> TYPE_REFERENCE = new TypeReference<Result<TopNResultValue>>(){};
+  private static final TypeReference<Result<TopNResultValue>> TYPE_REFERENCE = new TypeReference<Result<TopNResultValue>>()
-
+  {
-  private static final TypeReference<Object> OBJECT_TYPE_REFERENCE = new TypeReference<Object>(){};
+  };
+  private static final TypeReference<Object> OBJECT_TYPE_REFERENCE = new TypeReference<Object>()
+  {
+  };
   private final TopNQueryConfig config;
 
   @Inject
@@ -161,7 +163,12 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
                       values.put(agg.getName(), fn.manipulate(agg, input.getMetric(agg.getName())));
                     }
                     for (PostAggregator postAgg : query.getPostAggregatorSpecs()) {
-                      values.put(postAgg.getName(), input.getMetric(postAgg.getName()));
+                      Object calculatedPostAgg = input.getMetric(postAgg.getName());
+                      if (calculatedPostAgg != null) {
+                        values.put(postAgg.getName(), calculatedPostAgg);
+                      } else {
+                        values.put(postAgg.getName(), postAgg.compute(values));
+                      }
                     }
                     values.put(dimension, input.getDimensionValue(dimension));
 
@@ -281,10 +288,6 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
                 vals.put(factory.getName(), factory.deserialize(resultIter.next()));
               }
 
-              for (PostAggregator postAgg : postAggs) {
-                vals.put(postAgg.getName(), postAgg.compute(vals));
-              }
-
               retVal.add(vals);
             }
 
@@ -313,6 +316,11 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
     return new ThresholdAdjustingQueryRunner(runner, config.getMinTopNThreshold());
   }
 
+  public Ordering<Result<TopNResultValue>> getOrdering()
+  {
+    return Ordering.natural();
+  }
+
   private static class ThresholdAdjustingQueryRunner implements QueryRunner<Result<TopNResultValue>>
   {
     private final QueryRunner<Result<TopNResultValue>> runner;
@@ -397,9 +405,4 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
       );
     }
   }
-
-  public Ordering<Result<TopNResultValue>> getOrdering()
-  {
-    return Ordering.natural();
-  }
 }

processing/src/main/java/io/druid/query/topn/TopNResultBuilder.java

@@ -33,9 +33,7 @@ public interface TopNResultBuilder
   public TopNResultBuilder addEntry(
       String dimName,
       Object dimValIndex,
-      Object[] metricVals,
+      Object[] metricVals
-      List<AggregatorFactory> aggFactories,
-      List<PostAggregator> postAggs
   );
 
   public TopNResultBuilder addEntry(

processing/src/test/java/io/druid/query/QueryRunnerTestHelper.java

@@ -60,6 +60,7 @@ public class QueryRunnerTestHelper
   public static final String indexMetric = "index";
   public static final String uniqueMetric = "uniques";
   public static final String addRowsIndexConstantMetric = "addRowsIndexConstant";
+  public static String dependentPostAggMetric = "dependentPostAgg";
   public static final CountAggregatorFactory rowsCount = new CountAggregatorFactory("rows");
   public static final LongSumAggregatorFactory indexLongSum = new LongSumAggregatorFactory("index", "index");
   public static final DoubleSumAggregatorFactory indexDoubleSum = new DoubleSumAggregatorFactory("index", "index");
@@ -72,8 +73,19 @@ public class QueryRunnerTestHelper
   public static final FieldAccessPostAggregator indexPostAgg = new FieldAccessPostAggregator("index", "index");
   public static final ArithmeticPostAggregator addRowsIndexConstant =
       new ArithmeticPostAggregator(
-          "addRowsIndexConstant", "+", Lists.newArrayList(constant, rowsPostAgg, indexPostAgg)
+          addRowsIndexConstantMetric, "+", Lists.newArrayList(constant, rowsPostAgg, indexPostAgg)
       );
+  // dependent on AddRowsIndexContact postAgg
+  public static final ArithmeticPostAggregator dependentPostAgg = new ArithmeticPostAggregator(
+      dependentPostAggMetric,
+      "+",
+      Lists.newArrayList(
+          constant,
+          new FieldAccessPostAggregator(addRowsIndexConstantMetric, addRowsIndexConstantMetric)
+      )
+  );
+
+
   public static final List<AggregatorFactory> commonAggregators = Arrays.asList(
       rowsCount,
       indexDoubleSum,

processing/src/test/java/io/druid/query/aggregation/AggregatorUtilTest.java

@@ -0,0 +1,104 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013, 2014  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.query.aggregation;
+
+import com.google.common.collect.Lists;
+import io.druid.query.aggregation.post.ArithmeticPostAggregator;
+import io.druid.query.aggregation.post.ConstantPostAggregator;
+import io.druid.query.aggregation.post.FieldAccessPostAggregator;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.List;
+
+public class AggregatorUtilTest
+{
+
+  @Test
+  public void testPruneDependentPostAgg()
+  {
+    PostAggregator agg1 = new ArithmeticPostAggregator(
+        "abc", "+", Lists.<PostAggregator>newArrayList(
+        new ConstantPostAggregator("1", 1L, 1L), new ConstantPostAggregator("2", 2L, 2L)
+    )
+    );
+    PostAggregator dependency1 = new ArithmeticPostAggregator(
+        "dep1", "+", Lists.<PostAggregator>newArrayList(
+        new ConstantPostAggregator("1", 1L, 1L), new ConstantPostAggregator("4", 4L, 4L)
+    )
+    );
+    PostAggregator agg2 = new FieldAccessPostAggregator("def", "def");
+    PostAggregator dependency2 = new FieldAccessPostAggregator("dep2", "dep2");
+    PostAggregator aggregator = new ArithmeticPostAggregator(
+        "finalAgg",
+        "+",
+        Lists.<PostAggregator>newArrayList(
+            new FieldAccessPostAggregator("dep1", "dep1"),
+            new FieldAccessPostAggregator("dep2", "dep2")
+        )
+    );
+    List<PostAggregator> prunedAgg = AggregatorUtil.pruneDependentPostAgg(
+        Lists.newArrayList(
+            agg1,
+            dependency1,
+            agg2,
+            dependency2,
+            aggregator
+        ), aggregator.getName()
+    );
+    Assert.assertEquals(Lists.newArrayList(dependency1, dependency2, aggregator), prunedAgg);
+  }
+
+  @Test
+  public void testOutOfOrderPruneDependentPostAgg()
+  {
+    PostAggregator agg1 = new ArithmeticPostAggregator(
+        "abc", "+", Lists.<PostAggregator>newArrayList(
+        new ConstantPostAggregator("1", 1L, 1L), new ConstantPostAggregator("2", 2L, 2L)
+    )
+    );
+    PostAggregator dependency1 = new ArithmeticPostAggregator(
+        "dep1", "+", Lists.<PostAggregator>newArrayList(
+        new ConstantPostAggregator("1", 1L, 1L), new ConstantPostAggregator("4", 4L, 4L)
+    )
+    );
+    PostAggregator agg2 = new FieldAccessPostAggregator("def", "def");
+    PostAggregator dependency2 = new FieldAccessPostAggregator("dep2", "dep2");
+    PostAggregator aggregator = new ArithmeticPostAggregator(
+        "finalAgg",
+        "+",
+        Lists.<PostAggregator>newArrayList(
+            new FieldAccessPostAggregator("dep1", "dep1"),
+            new FieldAccessPostAggregator("dep2", "dep2")
+        )
+    );
+    List<PostAggregator> prunedAgg = AggregatorUtil.pruneDependentPostAgg(
+        Lists.newArrayList(
+            agg1,
+            dependency1,
+            aggregator, // dependency is added later than the aggregator
+            agg2,
+            dependency2
+        ), aggregator.getName()
+    );
+    Assert.assertEquals(Lists.newArrayList(dependency1, aggregator), prunedAgg);
+  }
+
+}

processing/src/test/java/io/druid/query/timeseries/TimeseriesBinaryFnTest.java

@@ -20,16 +20,11 @@
 package io.druid.query.timeseries;
 
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Lists;
 import io.druid.granularity.QueryGranularity;
 import io.druid.query.Result;
 import io.druid.query.aggregation.AggregatorFactory;
 import io.druid.query.aggregation.CountAggregatorFactory;
 import io.druid.query.aggregation.LongSumAggregatorFactory;
-import io.druid.query.aggregation.PostAggregator;
-import io.druid.query.aggregation.post.ArithmeticPostAggregator;
-import io.druid.query.aggregation.post.ConstantPostAggregator;
-import io.druid.query.aggregation.post.FieldAccessPostAggregator;
 import junit.framework.Assert;
 import org.joda.time.DateTime;
 import org.junit.Test;
@@ -43,21 +38,10 @@ public class TimeseriesBinaryFnTest
 {
   final CountAggregatorFactory rowsCount = new CountAggregatorFactory("rows");
   final LongSumAggregatorFactory indexLongSum = new LongSumAggregatorFactory("index", "index");
-  final ConstantPostAggregator constant = new ConstantPostAggregator("const", 1L, null);
-  final FieldAccessPostAggregator rowsPostAgg = new FieldAccessPostAggregator("rows", "rows");
-  final FieldAccessPostAggregator indexPostAgg = new FieldAccessPostAggregator("index", "index");
-  final ArithmeticPostAggregator addRowsIndexConstant = new ArithmeticPostAggregator(
-      "addRowsIndexConstant",
-      "+",
-      Lists.newArrayList(constant, rowsPostAgg, indexPostAgg)
-  );
   final List<AggregatorFactory> aggregatorFactories = Arrays.asList(
       rowsCount,
       indexLongSum
   );
-  final List<PostAggregator> postAggregators = Arrays.<PostAggregator>asList(
-      addRowsIndexConstant
-  );
   final DateTime currTime = new DateTime();
 
   @Test
@@ -87,16 +71,14 @@ public class TimeseriesBinaryFnTest
         new TimeseriesResultValue(
             ImmutableMap.<String, Object>of(
                 "rows", 3L,
-                "index", 5L,
+                "index", 5L
-                "addRowsIndexConstant", 9.0
             )
         )
     );
 
     Result<TimeseriesResultValue> actual = new TimeseriesBinaryFn(
         QueryGranularity.ALL,
-        aggregatorFactories,
+        aggregatorFactories
-        postAggregators
     ).apply(
         result1,
         result2
@@ -131,16 +113,14 @@ public class TimeseriesBinaryFnTest
         new TimeseriesResultValue(
             ImmutableMap.<String, Object>of(
                 "rows", 3L,
-                "index", 5L,
+                "index", 5L
-                "addRowsIndexConstant", 9.0
             )
         )
     );
 
     Result<TimeseriesResultValue> actual = new TimeseriesBinaryFn(
         QueryGranularity.DAY,
-        aggregatorFactories,
+        aggregatorFactories
-        postAggregators
     ).apply(
         result1,
         result2
@@ -166,8 +146,7 @@ public class TimeseriesBinaryFnTest
 
     Result<TimeseriesResultValue> actual = new TimeseriesBinaryFn(
         QueryGranularity.ALL,
-        aggregatorFactories,
+        aggregatorFactories
-        postAggregators
     ).apply(
         result1,
         result2
@@ -202,16 +181,14 @@ public class TimeseriesBinaryFnTest
         new TimeseriesResultValue(
             ImmutableMap.<String, Object>of(
                 "rows", 3L,
-                "index", 5L,
+                "index", 5L
-                "addRowsIndexConstant", 9.0
             )
         )
     );
 
     Result<TimeseriesResultValue> actual = new TimeseriesBinaryFn(
         QueryGranularity.ALL,
-        aggregatorFactories,
+        aggregatorFactories
-        postAggregators
     ).apply(
         result1,
         result2

processing/src/test/java/io/druid/query/topn/TopNBinaryFnBenchmark.java

@@ -0,0 +1,135 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013, 2014  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.query.topn;
+
+import com.google.caliper.Param;
+import com.google.caliper.Runner;
+import com.google.caliper.SimpleBenchmark;
+import com.google.common.collect.Lists;
+import io.druid.granularity.QueryGranularity;
+import io.druid.query.Result;
+import io.druid.query.aggregation.AggregatorFactory;
+import io.druid.query.aggregation.CountAggregatorFactory;
+import io.druid.query.aggregation.LongSumAggregatorFactory;
+import io.druid.query.aggregation.PostAggregator;
+import io.druid.query.aggregation.post.ArithmeticPostAggregator;
+import io.druid.query.aggregation.post.ConstantPostAggregator;
+import io.druid.query.aggregation.post.FieldAccessPostAggregator;
+import io.druid.query.dimension.DefaultDimensionSpec;
+import org.joda.time.DateTime;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class TopNBinaryFnBenchmark extends SimpleBenchmark
+{
+  @Param({"1", "5", "10", "15"})
+  int aggCount;
+  @Param({"1", "5", "10", "15"})
+  int postAggCount;
+  @Param({"1000", "10000"})
+  int threshold;
+  Result<TopNResultValue> result1;
+  Result<TopNResultValue> result2;
+  TopNBinaryFn fn;
+
+  public static void main(String[] args) throws Exception
+  {
+    Runner.main(TopNBinaryFnBenchmark.class, args);
+  }
+
+  @Override
+  protected void setUp() throws Exception
+  {
+
+    final ConstantPostAggregator constant = new ConstantPostAggregator("const", 1L, null);
+    final FieldAccessPostAggregator rowsPostAgg = new FieldAccessPostAggregator("rows", "rows");
+    final FieldAccessPostAggregator indexPostAgg = new FieldAccessPostAggregator("index", "index");
+
+
+    final List<AggregatorFactory> aggregatorFactories = new ArrayList<>();
+    aggregatorFactories.add(new CountAggregatorFactory("rows"));
+    aggregatorFactories.add(new LongSumAggregatorFactory("index", "index"));
+    for (int i = 1; i < aggCount; i++) {
+      aggregatorFactories.add(new CountAggregatorFactory("rows" + i));
+    }
+    final List<PostAggregator> postAggregators = new ArrayList<>();
+    for (int i = 0; i < postAggCount; i++) {
+      postAggregators.add(
+          new ArithmeticPostAggregator(
+              "addrowsindexconstant" + i,
+              "+",
+              Lists.newArrayList(constant, rowsPostAgg, indexPostAgg)
+          )
+      );
+    }
+    final DateTime currTime = new DateTime();
+    List<Map<String, Object>> list = new ArrayList<>();
+    for (int i = 0; i < threshold; i++) {
+      Map<String, Object> res = new HashMap<>();
+      res.put("testdim", "" + i);
+      res.put("rows", 1L);
+      for (int j = 0; j < aggCount; j++) {
+        res.put("rows" + j, 1L);
+      }
+      res.put("index", 1L);
+      list.add(res);
+    }
+    result1 = new Result<>(
+        currTime,
+        new TopNResultValue(list)
+    );
+
+    List<Map<String, Object>> list2 = new ArrayList<>();
+    for (int i = 0; i < threshold; i++) {
+      Map<String, Object> res = new HashMap<>();
+      res.put("testdim", "" + i);
+      res.put("rows", 2L);
+      for (int j = 0; j < aggCount; j++) {
+        res.put("rows" + j, 2L);
+      }
+      res.put("index", 2L);
+      list2.add(res);
+    }
+    result2 = new Result<>(
+        currTime,
+        new TopNResultValue(list2)
+    );
+    fn = new TopNBinaryFn(
+        TopNResultMerger.identity,
+        QueryGranularity.ALL,
+        new DefaultDimensionSpec("testdim", null),
+        new NumericTopNMetricSpec("index"),
+        100,
+        aggregatorFactories,
+        postAggregators
+    );
+  }
+
+  public void timeMerge(int nReps)
+  {
+    for (int i = 0; i < nReps; i++) {
+      fn.apply(result1, result2);
+    }
+  }
+
+}

processing/src/test/java/io/druid/query/topn/TopNBinaryFnTest.java

@@ -129,15 +129,13 @@ public class TopNBinaryFnTest
                 ImmutableMap.<String, Object>of(
                     "testdim", "1",
                     "rows", 3L,
-                    "index", 5L,
+                    "index", 5L
-                    "addrowsindexconstant", 9.0
                 ),
 
                 ImmutableMap.<String, Object>of(
                     "testdim", "2",
                     "rows", 4L,
-                    "index", 4L,
+                    "index", 4L
-                    "addrowsindexconstant", 9.0
                 )
             )
         )
@@ -214,14 +212,12 @@ public class TopNBinaryFnTest
                 ImmutableMap.<String, Object>of(
                     "testdim", "1",
                     "rows", 3L,
-                    "index", 5L,
+                    "index", 5L
-                    "addrowsindexconstant", 9.0
                 ),
                 ImmutableMap.<String, Object>of(
                     "testdim", "2",
                     "rows", 4L,
-                    "index", 4L,
+                    "index", 4L
-                    "addrowsindexconstant", 9.0
                 )
             )
         )
@@ -427,15 +423,12 @@ public class TopNBinaryFnTest
                 ImmutableMap.<String, Object>of(
                     "testdim", "1",
                     "rows", 3L,
-                    "index", 5L,
+                    "index", 5L
-                    "addrowsindexconstant", 9.0
                 ),
                 ImmutableMap.<String, Object>of(
                     "testdim", "2",
                     "rows", 4L,
-                    "index", 4L,
+                    "index", 4L                )
-                    "addrowsindexconstant", 9.0
-                )
             )
         )
     );

processing/src/test/java/io/druid/query/topn/TopNQueryRunnerTest.java

@@ -1176,4 +1176,75 @@ public class TopNQueryRunnerTest
 
     TestHelper.assertExpectedResults(expectedResults, runner.run(query));
   }
+
+  @Test
+  public void testTopNDependentPostAgg() {
+    TopNQuery query = new TopNQueryBuilder()
+        .dataSource(QueryRunnerTestHelper.dataSource)
+        .granularity(QueryRunnerTestHelper.allGran)
+        .dimension(providerDimension)
+        .metric(QueryRunnerTestHelper.dependentPostAggMetric)
+        .threshold(4)
+        .intervals(QueryRunnerTestHelper.fullOnInterval)
+        .aggregators(
+            Lists.<AggregatorFactory>newArrayList(
+                Iterables.concat(
+                    QueryRunnerTestHelper.commonAggregators,
+                    Lists.newArrayList(
+                        new MaxAggregatorFactory("maxIndex", "index"),
+                        new MinAggregatorFactory("minIndex", "index")
+                    )
+                )
+            )
+        )
+        .postAggregators(
+            Arrays.<PostAggregator>asList(
+                QueryRunnerTestHelper.addRowsIndexConstant,
+                QueryRunnerTestHelper.dependentPostAgg
+            )
+        )
+        .build();
+
+    List<Result<TopNResultValue>> expectedResults = Arrays.asList(
+        new Result<TopNResultValue>(
+            new DateTime("2011-01-12T00:00:00.000Z"),
+            new TopNResultValue(
+                Arrays.<Map<String, Object>>asList(
+                    ImmutableMap.<String, Object>builder()
+                                .put(providerDimension, "total_market")
+                                .put("rows", 186L)
+                                .put("index", 215679.82879638672D)
+                                .put("addRowsIndexConstant", 215866.82879638672D)
+                                .put(QueryRunnerTestHelper.dependentPostAggMetric, 215867.82879638672D)
+                                .put("uniques", QueryRunnerTestHelper.UNIQUES_2)
+                                .put("maxIndex", 1743.9217529296875D)
+                                .put("minIndex", 792.3260498046875D)
+                                .build(),
+                    ImmutableMap.<String, Object>builder()
+                                .put(providerDimension, "upfront")
+                                .put("rows", 186L)
+                                .put("index", 192046.1060180664D)
+                                .put("addRowsIndexConstant", 192233.1060180664D)
+                                .put(QueryRunnerTestHelper.dependentPostAggMetric, 192234.1060180664D)
+                                .put("uniques", QueryRunnerTestHelper.UNIQUES_2)
+                                .put("maxIndex", 1870.06103515625D)
+                                .put("minIndex", 545.9906005859375D)
+                                .build(),
+                    ImmutableMap.<String, Object>builder()
+                                .put(providerDimension, "spot")
+                                .put("rows", 837L)
+                                .put("index", 95606.57232284546D)
+                                .put("addRowsIndexConstant", 96444.57232284546D)
+                                .put(QueryRunnerTestHelper.dependentPostAggMetric, 96445.57232284546D)
+                                .put("uniques", QueryRunnerTestHelper.UNIQUES_9)
+                                .put("maxIndex", 277.2735290527344D)
+                                .put("minIndex", 59.02102279663086D)
+                                .build()
+                )
+            )
+        )
+    );
+
+    TestHelper.assertExpectedResults(expectedResults, runner.run(query));
+  }
 }

server/src/main/java/io/druid/client/cache/LocalCacheProvider.java

@@ -29,7 +29,7 @@ public class LocalCacheProvider implements CacheProvider
 {
   @JsonProperty
   @Min(0)
-  private long sizeInBytes = 10485760;
+  private long sizeInBytes = 0;
 
   @JsonProperty
   @Min(0)

server/src/main/java/io/druid/segment/realtime/plumber/RealtimePlumber.java

@@ -68,7 +68,6 @@ import java.util.concurrent.ScheduledExecutorService;
 public class RealtimePlumber implements Plumber
 {
   private static final EmittingLogger log = new EmittingLogger(RealtimePlumber.class);
-
   private final Period windowPeriod;
   private final File basePersistDirectory;
   private final IndexGranularity segmentGranularity;
@@ -84,16 +83,15 @@ public class RealtimePlumber implements Plumber
   private final SegmentPublisher segmentPublisher;
   private final ServerView serverView;
   private final int maxPendingPersists;
-
   private final Object handoffCondition = new Object();
   private final Map<Long, Sink> sinks = Maps.newConcurrentMap();
   private final VersionedIntervalTimeline<String, Sink> sinkTimeline = new VersionedIntervalTimeline<String, Sink>(
       String.CASE_INSENSITIVE_ORDER
   );
-
   private volatile boolean shuttingDown = false;
   private volatile boolean stopped = false;
   private volatile ExecutorService persistExecutor = null;
+  private volatile ExecutorService mergeExecutor = null;
   private volatile ScheduledExecutorService scheduledExecutor = null;
 
   public RealtimePlumber(
@@ -300,13 +298,13 @@ public class RealtimePlumber implements Plumber
     );
   }
 
-  // Submits persist-n-merge task for a Sink to the persistExecutor
+  // Submits persist-n-merge task for a Sink to the mergeExecutor
   private void persistAndMerge(final long truncatedTime, final Sink sink)
   {
     final String threadName = String.format(
         "%s-%s-persist-n-merge", schema.getDataSource(), new DateTime(truncatedTime)
     );
-    persistExecutor.execute(
+    mergeExecutor.execute(
         new ThreadRenamingRunnable(threadName)
         {
           @Override
@@ -431,6 +429,13 @@ public class RealtimePlumber implements Plumber
           "plumber_persist_%d", maxPendingPersists
       );
     }
+    if (mergeExecutor == null) {
+      // use a blocking single threaded executor to throttle the firehose when write to disk is slow
+      mergeExecutor = Execs.newBlockingSingleThreaded(
+          "plumber_merge_%d", 1
+      );
+    }
+
     if (scheduledExecutor == null) {
       scheduledExecutor = Executors.newScheduledThreadPool(
           1,
@@ -592,7 +597,11 @@ public class RealtimePlumber implements Plumber
                     log.info("Adding entry[%s] for merge and push.", entry);
                     sinksToPush.add(entry);
                   } else {
-                    log.warn("[%s] < [%s] Skipping persist and merge.", new DateTime(intervalStart), minTimestampAsDate);
+                    log.warn(
+                        "[%s] < [%s] Skipping persist and merge.",
+                        new DateTime(intervalStart),
+                        minTimestampAsDate
+                    );
                   }
                 }
 
@@ -660,39 +669,46 @@ public class RealtimePlumber implements Plumber
    */
   protected int persistHydrant(FireHydrant indexToPersist, Schema schema, Interval interval)
   {
-    if (indexToPersist.hasSwapped()) {
+    synchronized (indexToPersist) {
+      if (indexToPersist.hasSwapped()) {
+        log.info(
+            "DataSource[%s], Interval[%s], Hydrant[%s] already swapped. Ignoring request to persist.",
+            schema.getDataSource(), interval, indexToPersist
+        );
+        return 0;
+      }
+
       log.info(
-          "DataSource[%s], Interval[%s], Hydrant[%s] already swapped. Ignoring request to persist.",
+          "DataSource[%s], Interval[%s], persisting Hydrant[%s]",
-          schema.getDataSource(), interval, indexToPersist
+          schema.getDataSource(),
+          interval,
+          indexToPersist
       );
-      return 0;
+      try {
-    }
+        int numRows = indexToPersist.getIndex().size();
 
-    log.info("DataSource[%s], Interval[%s], persisting Hydrant[%s]", schema.getDataSource(), interval, indexToPersist);
+        File persistedFile = IndexMerger.persist(
-    try {
+            indexToPersist.getIndex(),
-      int numRows = indexToPersist.getIndex().size();
+            new File(computePersistDir(schema, interval), String.valueOf(indexToPersist.getCount()))
+        );
 
-      File persistedFile = IndexMerger.persist(
+        indexToPersist.swapSegment(
-          indexToPersist.getIndex(),
+            new QueryableIndexSegment(
-          new File(computePersistDir(schema, interval), String.valueOf(indexToPersist.getCount()))
+                indexToPersist.getSegment().getIdentifier(),
-      );
+                IndexIO.loadIndex(persistedFile)
+            )
+        );
 
-      indexToPersist.swapSegment(
+        return numRows;
-          new QueryableIndexSegment(
+      }
-              indexToPersist.getSegment().getIdentifier(),
+      catch (IOException e) {
-              IndexIO.loadIndex(persistedFile)
+        log.makeAlert("dataSource[%s] -- incremental persist failed", schema.getDataSource())
-          )
+           .addData("interval", interval)
-      );
+           .addData("count", indexToPersist.getCount())
+           .emit();
 
-      return numRows;
+        throw Throwables.propagate(e);
-    }
+      }
-    catch (IOException e) {
-      log.makeAlert("dataSource[%s] -- incremental persist failed", schema.getDataSource())
-         .addData("interval", interval)
-         .addData("count", indexToPersist.getCount())
-         .emit();
-
-      throw Throwables.propagate(e);
     }
   }
 

server/src/test/java/io/druid/client/CachingClusteredClientTest.java

@@ -47,6 +47,7 @@ import io.druid.jackson.DefaultObjectMapper;
 import io.druid.query.BySegmentResultValueClass;
 import io.druid.query.DataSource;
 import io.druid.query.Druids;
+import io.druid.query.FinalizeResultsQueryRunner;
 import io.druid.query.MapQueryToolChestWarehouse;
 import io.druid.query.Query;
 import io.druid.query.QueryConfig;
@@ -115,17 +116,21 @@ import java.util.concurrent.Executor;
 @RunWith(Parameterized.class)
 public class CachingClusteredClientTest
 {
+  public static final ImmutableMap<String, Object> CONTEXT = ImmutableMap.of();
+  public static final MultipleIntervalSegmentSpec SEG_SPEC = new MultipleIntervalSegmentSpec(ImmutableList.<Interval>of());
+  public static final String DATA_SOURCE = "test";
+  protected static final DefaultObjectMapper jsonMapper = new DefaultObjectMapper(new SmileFactory());
+
+  static {
+    jsonMapper.getFactory().setCodec(jsonMapper);
+  }
+
   /**
    * We want a deterministic test, but we'd also like a bit of randomness for the distribution of segments
    * across servers.  Thus, we loop multiple times and each time use a deterministically created Random instance.
    * Increase this value to increase exposure to random situations at the expense of test run time.
    */
   private static final int RANDOMNESS = 10;
-
-  public static final ImmutableMap<String, Object> CONTEXT = ImmutableMap.of();
-  public static final MultipleIntervalSegmentSpec SEG_SPEC = new MultipleIntervalSegmentSpec(ImmutableList.<Interval>of());
-  public static final String DATA_SOURCE = "test";
-
   private static final List<AggregatorFactory> AGGS = Arrays.asList(
       new CountAggregatorFactory("rows"),
       new LongSumAggregatorFactory("imps", "imps"),
@@ -152,6 +157,17 @@ public class CachingClusteredClientTest
   private static final DateTimeZone TIMEZONE = DateTimeZone.forID("America/Los_Angeles");
   private static final QueryGranularity PT1H_TZ_GRANULARITY = new PeriodGranularity(new Period("PT1H"), null, TIMEZONE);
   private static final String TOP_DIM = "a_dim";
+  private final Random random;
+  protected VersionedIntervalTimeline<String, ServerSelector> timeline;
+  protected TimelineServerView serverView;
+  protected Cache cache;
+  public CachingClusteredClient client;
+  DruidServer[] servers;
+
+  public CachingClusteredClientTest(int randomSeed)
+  {
+    this.random = new Random(randomSeed);
+  }
 
   @Parameterized.Parameters
   public static Collection<?> constructorFeeder() throws IOException
@@ -169,28 +185,6 @@ public class CachingClusteredClientTest
     );
   }
 
-
-  protected static final DefaultObjectMapper jsonMapper = new DefaultObjectMapper(new SmileFactory());
-
-  static {
-    jsonMapper.getFactory().setCodec(jsonMapper);
-  }
-
-  private final Random random;
-
-  protected VersionedIntervalTimeline<String, ServerSelector> timeline;
-  protected TimelineServerView serverView;
-  protected Cache cache;
-
-  CachingClusteredClient client;
-
-  DruidServer[] servers;
-
-  public CachingClusteredClientTest(int randomSeed)
-  {
-    this.random = new Random(randomSeed);
-  }
-
   @Before
   public void setUp() throws Exception
   {
@@ -222,7 +216,10 @@ public class CachingClusteredClientTest
                                                         .postAggregators(POST_AGGS)
                                                         .context(CONTEXT);
 
+    QueryRunner runner = new FinalizeResultsQueryRunner(client, new TimeseriesQueryQueryToolChest(new QueryConfig()));
+
     testQueryCaching(
+        runner,
         builder.build(),
         new Interval("2011-01-01/2011-01-02"), makeTimeResults(new DateTime("2011-01-01"), 50, 5000),
         new Interval("2011-01-02/2011-01-03"), makeTimeResults(new DateTime("2011-01-02"), 30, 6000),
@@ -263,7 +260,7 @@ public class CachingClusteredClientTest
             new DateTime("2011-01-09"), 18, 521,
             new DateTime("2011-01-09T01"), 181, 52
         ),
-        client.run(
+        runner.run(
             builder.intervals("2011-01-01/2011-01-10")
                    .aggregators(RENAMED_AGGS)
                    .postAggregators(RENAMED_POST_AGGS)
@@ -285,7 +282,10 @@ public class CachingClusteredClientTest
                                                         .postAggregators(POST_AGGS)
                                                         .context(CONTEXT);
 
+    QueryRunner runner = new FinalizeResultsQueryRunner(client, new TimeseriesQueryQueryToolChest(new QueryConfig()));
+
     testQueryCaching(
+        runner,
         builder.build(),
         new Interval("2011-11-04/2011-11-08"),
         makeTimeResults(
@@ -303,7 +303,7 @@ public class CachingClusteredClientTest
             new DateTime("2011-11-06", TIMEZONE), 23, 85312,
             new DateTime("2011-11-07", TIMEZONE), 85, 102
         ),
-        client.run(
+        runner.run(
             builder.intervals("2011-11-04/2011-11-08")
                    .aggregators(RENAMED_AGGS)
                    .postAggregators(RENAMED_POST_AGGS)
@@ -324,6 +324,7 @@ public class CachingClusteredClientTest
                                                         .postAggregators(POST_AGGS);
 
     testQueryCaching(
+        client,
         1,
         true,
         builder.context(
@@ -342,6 +343,7 @@ public class CachingClusteredClientTest
     cache.close("0_0");
 
     testQueryCaching(
+        client,
         1,
         false,
         builder.context(
@@ -358,6 +360,7 @@ public class CachingClusteredClientTest
     Assert.assertEquals(0, cache.getStats().getNumMisses());
 
     testQueryCaching(
+        client,
         1,
         false,
         builder.context(
@@ -390,7 +393,10 @@ public class CachingClusteredClientTest
         .postAggregators(POST_AGGS)
         .context(CONTEXT);
 
+    QueryRunner runner = new FinalizeResultsQueryRunner(client, new TopNQueryQueryToolChest(new TopNQueryConfig()));
+
     testQueryCaching(
+        runner,
         builder.build(),
         new Interval("2011-01-01/2011-01-02"),
         makeTopNResults(new DateTime("2011-01-01"), "a", 50, 5000, "b", 50, 4999, "c", 50, 4998),
@@ -432,7 +438,7 @@ public class CachingClusteredClientTest
             new DateTime("2011-01-09"), "a", 50, 4985, "b", 50, 4984, "c", 50, 4983,
             new DateTime("2011-01-09T01"), "a", 50, 4985, "b", 50, 4984, "c", 50, 4983
         ),
-        client.run(
+        runner.run(
             builder.intervals("2011-01-01/2011-01-10")
                    .metric("imps")
                    .aggregators(RENAMED_AGGS)
@@ -458,7 +464,10 @@ public class CachingClusteredClientTest
         .postAggregators(POST_AGGS)
         .context(CONTEXT);
 
+    QueryRunner runner = new FinalizeResultsQueryRunner(client, new TopNQueryQueryToolChest(new TopNQueryConfig()));
+
     testQueryCaching(
+        runner,
         builder.build(),
         new Interval("2011-11-04/2011-11-08"),
         makeTopNResults(
@@ -477,7 +486,7 @@ public class CachingClusteredClientTest
             new DateTime("2011-11-06", TIMEZONE), "a", 50, 4991, "b", 50, 4990, "c", 50, 4989,
             new DateTime("2011-11-07", TIMEZONE), "a", 50, 4988, "b", 50, 4987, "c", 50, 4986
         ),
-        client.run(
+        runner.run(
             builder.intervals("2011-11-04/2011-11-08")
                    .metric("imps")
                    .aggregators(RENAMED_AGGS)
@@ -503,7 +512,9 @@ public class CachingClusteredClientTest
         .postAggregators(POST_AGGS)
         .context(CONTEXT);
 
+    QueryRunner runner = new FinalizeResultsQueryRunner(client, new TopNQueryQueryToolChest(new TopNQueryConfig()));
     testQueryCaching(
+        runner,
         builder.build(),
         new Interval("2011-01-01/2011-01-02"),
         makeTopNResults(),
@@ -530,6 +541,7 @@ public class CachingClusteredClientTest
         )
     );
 
+
     TestHelper.assertExpectedResults(
         makeRenamedTopNResults(
             new DateTime("2011-01-05"), "a", 50, 4994, "b", 50, 4993, "c", 50, 4992,
@@ -543,7 +555,7 @@ public class CachingClusteredClientTest
             new DateTime("2011-01-09"), "a", 50, 4985, "b", 50, 4984, "c", 50, 4983,
             new DateTime("2011-01-09T01"), "a", 50, 4985, "b", 50, 4984, "c", 50, 4983
         ),
-        client.run(
+        runner.run(
             builder.intervals("2011-01-01/2011-01-10")
                    .metric("imps")
                    .aggregators(RENAMED_AGGS)
@@ -557,6 +569,7 @@ public class CachingClusteredClientTest
   public void testSearchCaching() throws Exception
   {
     testQueryCaching(
+        client,
         new SearchQuery(
             new TableDataSource(DATA_SOURCE),
             DIM_FILTER,
@@ -594,13 +607,14 @@ public class CachingClusteredClientTest
     );
   }
 
-  public void testQueryCaching(final Query query, Object... args)
+  public void testQueryCaching(QueryRunner runner, final Query query, Object... args)
   {
-    testQueryCaching(3, true, query, args);
+    testQueryCaching(runner, 3, true, query, args);
   }
 
   @SuppressWarnings("unchecked")
   public void testQueryCaching(
+      final QueryRunner runner,
       final int numTimesToQuery,
       boolean expectBySegment,
       final Query query, Object... args // does this assume query intervals must be ordered?
@@ -754,7 +768,7 @@ public class CachingClusteredClientTest
                                 }
                             )
                     ),
-                    client.run(
+                    runner.run(
                         query.withQuerySegmentSpec(
                             new MultipleIntervalSegmentSpec(
                                 Arrays.asList(
@@ -774,7 +788,7 @@ public class CachingClusteredClientTest
       for (Capture queryCapture : queryCaptures) {
         Query capturedQuery = (Query) queryCapture.getValue();
         if (expectBySegment) {
-          Assert.assertEquals(true, capturedQuery.<Boolean>getContextValue("bySegment"));
+          Assert.assertEquals(true, capturedQuery.getContextValue("bySegment"));
         } else {
           Assert.assertTrue(
               capturedQuery.getContextValue("bySegment") == null ||
@@ -1253,6 +1267,8 @@ public class CachingClusteredClientTest
 
     private class MyDataSegment extends DataSegment
     {
+      private final DataSegment baseSegment = segment;
+
       private MyDataSegment()
       {
         super(
@@ -1268,8 +1284,6 @@ public class CachingClusteredClientTest
         );
       }
 
-      private final DataSegment baseSegment = segment;
-
       @Override
       @JsonProperty
       public String getDataSource()
@@ -1370,7 +1384,6 @@ public class CachingClusteredClientTest
   {
     private final DruidServer server;
     private final QueryRunner queryRunner;
-
     private final List<ServerExpectation> expectations = Lists.newArrayList();
 
     public ServerExpectations(

services/src/main/java/io/druid/cli/CliHistorical.java

@@ -26,6 +26,7 @@ import com.metamx.common.logger.Logger;
 import io.airlift.command.Command;
 import io.druid.client.cache.Cache;
 import io.druid.client.cache.CacheConfig;
+import io.druid.client.cache.CacheMonitor;
 import io.druid.client.cache.CacheProvider;
 import io.druid.guice.Jerseys;
 import io.druid.guice.JsonConfigProvider;
@@ -38,6 +39,7 @@ import io.druid.server.QueryResource;
 import io.druid.server.coordination.ServerManager;
 import io.druid.server.coordination.ZkCoordinator;
 import io.druid.server.initialization.JettyServerInitializer;
+import io.druid.server.metrics.MetricsModule;
 import org.eclipse.jetty.server.Server;
 
 import java.util.List;
@@ -77,10 +79,11 @@ public class CliHistorical extends ServerRunnable
 
             LifecycleModule.register(binder, ZkCoordinator.class);
             LifecycleModule.register(binder, Server.class);
+
             binder.bind(Cache.class).toProvider(CacheProvider.class).in(ManageLifecycle.class);
             JsonConfigProvider.bind(binder, "druid.historical.cache", CacheProvider.class);
             JsonConfigProvider.bind(binder, "druid.historical.cache", CacheConfig.class);
-
+            MetricsModule.register(binder, CacheMonitor.class);
           }
         }
     );