1) Take in g9yuayon's pull request, fix merge conflicts and formatting

client/src/main/java/com/metamx/druid/query/group/GroupByQuery.java

@@ -22,11 +22,14 @@ package com.metamx.druid.query.group;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.base.Function;
+import com.google.common.base.Functions;
 import com.google.common.base.Preconditions;
+import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
 import com.metamx.common.ISE;
 import com.metamx.common.guava.Sequence;
+import com.metamx.common.guava.Sequences;
 import com.metamx.druid.BaseQuery;
 import com.metamx.druid.Query;
 import com.metamx.druid.QueryGranularity;
@@ -37,13 +40,15 @@ import com.metamx.druid.query.Queries;
 import com.metamx.druid.query.dimension.DefaultDimensionSpec;
 import com.metamx.druid.query.dimension.DimensionSpec;
 import com.metamx.druid.query.filter.DimFilter;
-import com.metamx.druid.query.group.limit.DefaultLimitSpec;
+import com.metamx.druid.query.group.having.HavingSpec;
-import com.metamx.druid.query.group.limit.LimitSpec;
+import com.metamx.druid.query.group.orderby.DefaultLimitSpec;
-import com.metamx.druid.query.group.limit.NoopLimitSpec;
+import com.metamx.druid.query.group.orderby.LimitSpec;
-import com.metamx.druid.query.group.limit.OrderByColumnSpec;
+import com.metamx.druid.query.group.orderby.NoopLimitSpec;
+import com.metamx.druid.query.group.orderby.OrderByColumnSpec;
 import com.metamx.druid.query.segment.LegacySegmentSpec;
 import com.metamx.druid.query.segment.QuerySegmentSpec;
 
+import javax.annotation.Nullable;
 import java.util.List;
 import java.util.Map;
 
@@ -57,6 +62,7 @@ public class GroupByQuery extends BaseQuery<Row>
   }
 
   private final LimitSpec limitSpec;
+  private final HavingSpec havingSpec;
   private final DimFilter dimFilter;
   private final QueryGranularity granularity;
   private final List<DimensionSpec> dimensions;
@@ -69,34 +75,88 @@ public class GroupByQuery extends BaseQuery<Row>
   public GroupByQuery(
       @JsonProperty("dataSource") String dataSource,
       @JsonProperty("intervals") QuerySegmentSpec querySegmentSpec,
-      @JsonProperty("limitSpec") LimitSpec limitSpec,
       @JsonProperty("filter") DimFilter dimFilter,
       @JsonProperty("granularity") QueryGranularity granularity,
       @JsonProperty("dimensions") List<DimensionSpec> dimensions,
       @JsonProperty("aggregations") List<AggregatorFactory> aggregatorSpecs,
       @JsonProperty("postAggregations") List<PostAggregator> postAggregatorSpecs,
+      @JsonProperty("having") HavingSpec havingSpec,
+      @JsonProperty("limitSpec") LimitSpec limitSpec,
+      @JsonProperty("orderBy") LimitSpec orderBySpec,
       @JsonProperty("context") Map<String, String> context
   )
   {
     super(dataSource, querySegmentSpec, context);
-    this.limitSpec = (limitSpec == null) ? new NoopLimitSpec() : limitSpec;
     this.dimFilter = dimFilter;
     this.granularity = granularity;
     this.dimensions = dimensions == null ? ImmutableList.<DimensionSpec>of() : dimensions;
     this.aggregatorSpecs = aggregatorSpecs;
     this.postAggregatorSpecs = postAggregatorSpecs == null ? ImmutableList.<PostAggregator>of() : postAggregatorSpecs;
+    this.havingSpec = havingSpec;
+    this.limitSpec = (limitSpec == null) ? (orderBySpec == null ? new NoopLimitSpec() : orderBySpec) : limitSpec;
 
     Preconditions.checkNotNull(this.granularity, "Must specify a granularity");
     Preconditions.checkNotNull(this.aggregatorSpecs, "Must specify at least one aggregator");
     Queries.verifyAggregations(this.aggregatorSpecs, this.postAggregatorSpecs);
 
-    orderByLimitFn = this.limitSpec.build(this.dimensions, this.aggregatorSpecs, this.postAggregatorSpecs);
+    Function<Sequence<Row>, Sequence<Row>> postProcFn =
+        this.limitSpec.build(this.dimensions, this.aggregatorSpecs, this.postAggregatorSpecs);
+
+    if (havingSpec != null) {
+      postProcFn = Functions.compose(
+          new Function<Sequence<Row>, Sequence<Row>>()
+          {
+            @Override
+            public Sequence<Row> apply(@Nullable Sequence<Row> input)
+            {
+              return Sequences.filter(
+                  input,
+                  new Predicate<Row>()
+                  {
+                    @Override
+                    public boolean apply(@Nullable Row input)
+                    {
+                      return GroupByQuery.this.havingSpec.eval(input);
+                    }
+                  }
+              );
+            }
+          },
+          postProcFn
+      );
     }
 
-  @JsonProperty
+    orderByLimitFn = postProcFn;
-  public LimitSpec getLimitSpec()
+  }
+
+  /**
+   * A private constructor that avoids all of the various state checks.  Used by the with*() methods where the checks
+   * have already passed in order for the object to exist.
+   */
+  private GroupByQuery(
+      String dataSource,
+      QuerySegmentSpec querySegmentSpec,
+      DimFilter dimFilter,
+      QueryGranularity granularity,
+      List<DimensionSpec> dimensions,
+      List<AggregatorFactory> aggregatorSpecs,
+      List<PostAggregator> postAggregatorSpecs,
+      HavingSpec havingSpec,
+      LimitSpec orderBySpec,
+      Function<Sequence<Row>, Sequence<Row>> orderByLimitFn,
+      Map<String, String> context
+  )
   {
-    return limitSpec;
+    super(dataSource, querySegmentSpec, context);
+
+    this.dimFilter = dimFilter;
+    this.granularity = granularity;
+    this.dimensions = dimensions;
+    this.aggregatorSpecs = aggregatorSpecs;
+    this.postAggregatorSpecs = postAggregatorSpecs;
+    this.havingSpec = havingSpec;
+    this.limitSpec = orderBySpec;
+    this.orderByLimitFn = orderByLimitFn;
   }
 
   @JsonProperty("filter")
@@ -129,6 +189,18 @@ public class GroupByQuery extends BaseQuery<Row>
     return postAggregatorSpecs;
   }
 
+  @JsonProperty("having")
+  public HavingSpec getHavingSpec()
+  {
+    return havingSpec;
+  }
+
+  @JsonProperty
+  public LimitSpec getOrderBy()
+  {
+    return limitSpec;
+  }
+
   @Override
   public boolean hasFilters()
   {
@@ -152,12 +224,14 @@ public class GroupByQuery extends BaseQuery<Row>
     return new GroupByQuery(
         getDataSource(),
         getQuerySegmentSpec(),
-        limitSpec,
         dimFilter,
         granularity,
         dimensions,
         aggregatorSpecs,
         postAggregatorSpecs,
+        havingSpec,
+        limitSpec,
+        orderByLimitFn,
         computeOverridenContext(contextOverride)
     );
   }
@@ -168,12 +242,14 @@ public class GroupByQuery extends BaseQuery<Row>
     return new GroupByQuery(
         getDataSource(),
         spec,
-        limitSpec,
         dimFilter,
         granularity,
         dimensions,
         aggregatorSpecs,
         postAggregatorSpecs,
+        havingSpec,
+        limitSpec,
+        orderByLimitFn,
         getContext()
     );
   }
@@ -187,6 +263,8 @@ public class GroupByQuery extends BaseQuery<Row>
     private List<DimensionSpec> dimensions;
     private List<AggregatorFactory> aggregatorSpecs;
     private List<PostAggregator> postAggregatorSpecs;
+    private HavingSpec havingSpec;
+
     private Map<String, String> context;
 
     private LimitSpec limitSpec = null;
@@ -205,6 +283,9 @@ public class GroupByQuery extends BaseQuery<Row>
       dimensions = builder.dimensions;
       aggregatorSpecs = builder.aggregatorSpecs;
       postAggregatorSpecs = builder.postAggregatorSpecs;
+      havingSpec = builder.havingSpec;
+      limit = builder.limit;
+
       context = builder.context;
     }
 
@@ -351,6 +432,20 @@ public class GroupByQuery extends BaseQuery<Row>
       return this;
     }
 
+    public Builder setHavingSpec(HavingSpec havingSpec)
+    {
+      this.havingSpec = havingSpec;
+
+      return this;
+    }
+
+    public Builder setLimit(Integer limit)
+    {
+      this.limit = limit;
+
+      return this;
+    }
+
     public Builder copy()
     {
       return new Builder(this);
@@ -361,20 +456,21 @@ public class GroupByQuery extends BaseQuery<Row>
       final LimitSpec theLimitSpec;
       if (limitSpec == null) {
         theLimitSpec = new DefaultLimitSpec(orderByColumnSpecs, limit);
-      }
+      } else {
-      else {
         theLimitSpec = limitSpec;
       }
 
       return new GroupByQuery(
           dataSource,
           querySegmentSpec,
-          theLimitSpec,
           dimFilter,
           granularity,
           dimensions,
           aggregatorSpecs,
           postAggregatorSpecs,
+          havingSpec,
+          null,
+          theLimitSpec,
           context
       );
     }

client/src/main/java/com/metamx/druid/query/group/having/AlwaysHavingSpec.java

@@ -0,0 +1,14 @@
+package com.metamx.druid.query.group.having;
+
+import com.metamx.druid.input.Row;
+
+/**
+ */
+public class AlwaysHavingSpec implements HavingSpec
+{
+  @Override
+  public boolean eval(Row row)
+  {
+    return true;
+  }
+}

client/src/main/java/com/metamx/druid/query/group/having/AndHavingSpec.java

@@ -0,0 +1,75 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.collect.ImmutableList;
+import com.metamx.druid.input.Row;
+
+import java.util.List;
+
+/**
+ * The logical "and" operator for the "having" clause.
+ */
+public class AndHavingSpec implements HavingSpec
+{
+  private List<HavingSpec> havingSpecs;
+
+  @JsonCreator
+  public AndHavingSpec(@JsonProperty("havingSpecs") List<HavingSpec> havingSpecs)
+  {
+    this.havingSpecs = havingSpecs == null ? ImmutableList.<HavingSpec>of() : havingSpecs;
+  }
+
+  @JsonProperty("havingSpecs")
+  public List<HavingSpec> getHavingSpecs()
+  {
+    return havingSpecs;
+  }
+
+  @Override
+  public boolean eval(Row row)
+  {
+    for (HavingSpec havingSpec : havingSpecs) {
+      if (!havingSpec.eval(row)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    AndHavingSpec that = (AndHavingSpec) o;
+
+    if (havingSpecs != null ? !havingSpecs.equals(that.havingSpecs) : that.havingSpecs != null) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    return havingSpecs != null ? havingSpecs.hashCode() : 0;
+  }
+
+  @Override
+  public String toString()
+  {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("AndHavingSpec");
+    sb.append("{havingSpecs=").append(havingSpecs);
+    sb.append('}');
+    return sb.toString();
+  }
+}

client/src/main/java/com/metamx/druid/query/group/having/EqualToHavingSpec.java

@@ -0,0 +1,94 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.metamx.druid.input.Row;
+
+/**
+ * The "=" operator in a "having" clause. This is similar to SQL's "having aggregation = value",
+ * except that in SQL an aggregation is an expression instead of an aggregation name as in Druid.
+ */
+public class EqualToHavingSpec implements HavingSpec
+{
+  private String aggregationName;
+  private Number value;
+
+  @JsonCreator
+  public EqualToHavingSpec(
+      @JsonProperty("aggregation") String aggName,
+      @JsonProperty("value") Number value
+  )
+  {
+    this.aggregationName = aggName;
+    this.value = value;
+  }
+
+  @JsonProperty("value")
+  public Number getValue()
+  {
+    return value;
+  }
+
+  @JsonProperty("aggregation")
+  public String getAggregationName()
+  {
+    return aggregationName;
+  }
+
+  @Override
+  public boolean eval(Row row)
+  {
+    float metricValue = row.getFloatMetric(aggregationName);
+
+    return Float.compare(value.floatValue(), metricValue) == 0;
+  }
+
+  /**
+   * This method treats internal value as double mainly for ease of test.
+   */
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    EqualToHavingSpec that = (EqualToHavingSpec) o;
+
+    if (aggregationName != null ? !aggregationName.equals(that.aggregationName) : that.aggregationName != null) {
+      return false;
+    }
+
+    if (value != null && that.value != null) {
+      return Double.compare(value.doubleValue(), that.value.doubleValue()) == 0;
+    }
+
+    if (value == null && that.value == null) {
+      return true;
+    }
+
+    return false;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    int result = aggregationName != null ? aggregationName.hashCode() : 0;
+    result = 31 * result + (value != null ? value.hashCode() : 0);
+    return result;
+  }
+
+  @Override
+  public String toString()
+  {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("EqualToHavingSpec");
+    sb.append("{aggregationName='").append(aggregationName).append('\'');
+    sb.append(", value=").append(value);
+    sb.append('}');
+    return sb.toString();
+  }
+}

client/src/main/java/com/metamx/druid/query/group/having/GreaterThanHavingSpec.java

@@ -0,0 +1,90 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.metamx.druid.input.Row;
+
+/**
+ * The ">" operator in a "having" clause. This is similar to SQL's "having aggregation > value",
+ * except that an aggregation in SQL is an expression instead of an aggregation name as in Druid.
+ */
+public class GreaterThanHavingSpec implements HavingSpec
+{
+  private String aggregationName;
+  private Number value;
+
+  @JsonCreator
+  public GreaterThanHavingSpec(
+      @JsonProperty("aggregation") String aggName,
+      @JsonProperty("value") Number value
+  )
+  {
+    this.aggregationName = aggName;
+    this.value = value;
+  }
+
+  @JsonProperty("aggregation")
+  public String getAggregationName()
+  {
+    return aggregationName;
+  }
+
+  @JsonProperty("value")
+  public Number getValue()
+  {
+    return value;
+  }
+
+  @Override
+  public boolean eval(Row row)
+  {
+    float metricValue = row.getFloatMetric(aggregationName);
+
+    return Float.compare(metricValue, value.floatValue()) > 0;
+  }
+
+  /**
+   * This method treats internal value as double mainly for ease of test.
+   */
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    GreaterThanHavingSpec that = (GreaterThanHavingSpec) o;
+
+    if (value != null && that.value != null) {
+      return Double.compare(value.doubleValue(), that.value.doubleValue()) == 0;
+    }
+
+    if (value == null && that.value == null) {
+      return true;
+    }
+
+    return false;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    int result = aggregationName != null ? aggregationName.hashCode() : 0;
+    result = 31 * result + (value != null ? value.hashCode() : 0);
+    return result;
+  }
+
+  @Override
+  public String toString()
+  {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("GreaterThanHavingSpec");
+    sb.append("{aggregationName='").append(aggregationName).append('\'');
+    sb.append(", value=").append(value);
+    sb.append('}');
+    return sb.toString();
+  }
+}

client/src/main/java/com/metamx/druid/query/group/having/HavingSpec.java

@@ -0,0 +1,51 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.metamx.druid.input.Row;
+
+/**
+ * A "having" clause that filters aggregated value. This is similar to SQL's "having"
+ * clause.
+ */
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = AlwaysHavingSpec.class)
+@JsonSubTypes(value = {
+    @JsonSubTypes.Type(name = "and", value = AndHavingSpec.class),
+    @JsonSubTypes.Type(name = "or", value = OrHavingSpec.class),
+    @JsonSubTypes.Type(name = "not", value = NotHavingSpec.class),
+    @JsonSubTypes.Type(name = "greaterThan", value = GreaterThanHavingSpec.class),
+    @JsonSubTypes.Type(name = "lessThan", value = LessThanHavingSpec.class),
+    @JsonSubTypes.Type(name = "equalTo", value = EqualToHavingSpec.class)
+})
+public interface HavingSpec
+{
+  /**
+   * Evaluates if a given row satisfies the having spec.
+   *
+   * @param row A Row of data that may contain aggregated values
+   *
+   * @return true if the given row satisfies the having spec. False otherwise.
+   *
+   * @see Row
+   */
+  public boolean eval(Row row);
+
+  // Atoms for easy combination, but for now they are mostly useful
+  // for testing.
+  /**
+   * A "having" spec that always evaluates to false
+   */
+  public static final HavingSpec NEVER = new HavingSpec()
+  {
+    @Override
+    public boolean eval(Row row)
+    {
+      return false;
+    }
+  };
+
+  /**
+   * A "having" spec that always evaluates to true
+   */
+  public static final HavingSpec ALWAYS = new AlwaysHavingSpec();
+}

client/src/main/java/com/metamx/druid/query/group/having/LessThanHavingSpec.java

@@ -0,0 +1,89 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.metamx.druid.input.Row;
+
+/**
+ * The "<" operator in a "having" clause. This is similar to SQL's "having aggregation < value",
+ * except that an aggregation in SQL is an expression instead of an aggregation name as in Druid.
+ */
+public class LessThanHavingSpec implements HavingSpec
+{
+  private String aggregationName;
+  private Number value;
+
+  public LessThanHavingSpec
+      (
+          @JsonProperty("aggregation") String aggName,
+          @JsonProperty("value") Number value
+      )
+  {
+    this.aggregationName = aggName;
+    this.value = value;
+  }
+
+  @JsonProperty("aggregation")
+  public String getAggregationName()
+  {
+    return aggregationName;
+  }
+
+  @JsonProperty("value")
+  public Number getValue()
+  {
+    return value;
+  }
+
+  @Override
+  public boolean eval(Row row)
+  {
+    float metricValue = row.getFloatMetric(aggregationName);
+
+    return Float.compare(metricValue, value.floatValue()) < 0;
+  }
+
+  /**
+   * This method treats internal value as double mainly for ease of test.
+   */
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    LessThanHavingSpec that = (LessThanHavingSpec) o;
+
+    if (value != null && that.value != null) {
+      return Double.compare(value.doubleValue(), that.value.doubleValue()) == 0;
+    }
+
+    if (value == null && that.value == null) {
+      return true;
+    }
+
+    return false;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    int result = aggregationName != null ? aggregationName.hashCode() : 0;
+    result = 31 * result + (value != null ? value.hashCode() : 0);
+    return result;
+  }
+
+  @Override
+  public String toString()
+  {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("LessThanHavingSpec");
+    sb.append("{aggregationName='").append(aggregationName).append('\'');
+    sb.append(", value=").append(value);
+    sb.append('}');
+    return sb.toString();
+  }
+}

client/src/main/java/com/metamx/druid/query/group/having/NotHavingSpec.java

@@ -0,0 +1,66 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.metamx.druid.input.Row;
+
+/**
+ * The logical "not" operator for the "having" clause.
+ */
+public class NotHavingSpec implements HavingSpec
+{
+  private HavingSpec havingSpec;
+
+  @JsonCreator
+  public NotHavingSpec(@JsonProperty("havingSpec") HavingSpec havingSpec)
+  {
+    this.havingSpec = havingSpec;
+  }
+
+  @JsonProperty("havingSpec")
+  public HavingSpec getHavingSpec()
+  {
+    return havingSpec;
+  }
+
+  @Override
+  public boolean eval(Row row)
+  {
+    return !havingSpec.eval(row);
+  }
+
+  @Override
+  public String toString()
+  {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("NotHavingSpec");
+    sb.append("{havingSpec=").append(havingSpec);
+    sb.append('}');
+    return sb.toString();
+  }
+
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    NotHavingSpec that = (NotHavingSpec) o;
+
+    if (havingSpec != null ? !havingSpec.equals(that.havingSpec) : that.havingSpec != null) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    return havingSpec != null ? havingSpec.hashCode() : 0;
+  }
+}

client/src/main/java/com/metamx/druid/query/group/having/OrHavingSpec.java

@@ -0,0 +1,67 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.collect.ImmutableList;
+import com.metamx.druid.input.Row;
+
+import java.util.List;
+
+/**
+ * The logical "or" operator for the "having" clause.
+ */
+public class OrHavingSpec implements HavingSpec
+{
+  private List<HavingSpec> havingSpecs;
+
+  @JsonCreator
+  public OrHavingSpec(@JsonProperty("havingSpecs") List<HavingSpec> havingSpecs) {
+    this.havingSpecs = havingSpecs == null ? ImmutableList.<HavingSpec>of() : havingSpecs;
+  }
+
+  @JsonProperty("havingSpecs")
+  public List<HavingSpec> getHavingSpecs(){
+    return havingSpecs;
+  }
+
+  @Override
+  public boolean eval(Row row)
+  {
+    for(HavingSpec havingSpec: havingSpecs) {
+      if(havingSpec.eval(row)){
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+
+    OrHavingSpec that = (OrHavingSpec) o;
+
+    if (havingSpecs != null ? !havingSpecs.equals(that.havingSpecs) : that.havingSpecs != null) return false;
+
+    return true;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    return havingSpecs != null ? havingSpecs.hashCode() : 0;
+  }
+
+  @Override
+  public String toString()
+  {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("OrHavingSpec");
+    sb.append("{havingSpecs=").append(havingSpecs);
+    sb.append('}');
+    return sb.toString();
+  }
+}

client/src/main/java/com/metamx/druid/query/group/orderby/DefaultLimitSpec.java

@@ -17,13 +17,14 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-package com.metamx.druid.query.group.limit;
+package com.metamx.druid.query.group.orderby;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Ordering;
 import com.google.common.primitives.Longs;
@@ -35,6 +36,8 @@ import com.metamx.druid.aggregation.post.PostAggregator;
 import com.metamx.druid.input.Row;
 import com.metamx.druid.query.dimension.DimensionSpec;
 
+import javax.annotation.Nullable;
+import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
@@ -55,7 +58,7 @@ public class DefaultLimitSpec implements LimitSpec
     this.columns = (columns == null) ? ImmutableList.<OrderByColumnSpec>of() : columns;
     this.limit = (limit == null) ? Integer.MAX_VALUE : limit;
 
-    Preconditions.checkState(limit > 0, "limit[%s] must be >0", limit);
+    Preconditions.checkArgument(this.limit > 0, "limit[%s] must be >0", limit);
   }
 
   @JsonProperty
@@ -75,20 +78,22 @@ public class DefaultLimitSpec implements LimitSpec
       List<DimensionSpec> dimensions, List<AggregatorFactory> aggs, List<PostAggregator> postAggs
   )
   {
+    if (columns.isEmpty()) {
+      return new LimitingFn(limit);
+    }
+
     // Materialize the Comparator first for fast-fail error checking.
-    final Comparator<Row> comparator = makeComparator(dimensions, aggs, postAggs);
+    final Ordering<Row> ordering = makeComparator(dimensions, aggs, postAggs);
 
-    return new Function<Sequence<Row>, Sequence<Row>>()
+    if (limit == Integer.MAX_VALUE) {
-    {
+      return new SortingFn(ordering);
-      @Override
+    }
-      public Sequence<Row> apply(Sequence<Row> input)
+    else {
-      {
+      return new TopNFunction(ordering, limit);
-        return Sequences.limit(Sequences.sort(input, comparator), limit);
     }
-    };
   }
 
-  private Comparator<Row> makeComparator(
+  private Ordering<Row> makeComparator(
       List<DimensionSpec> dimensions, List<AggregatorFactory> aggs, List<PostAggregator> postAggs
   )
   {
@@ -174,4 +179,57 @@ public class DefaultLimitSpec implements LimitSpec
            ", limit=" + limit +
            '}';
   }
+
+  private static class LimitingFn implements Function<Sequence<Row>, Sequence<Row>>
+  {
+    private int limit;
+
+    public LimitingFn(int limit)
+    {
+      this.limit = limit;
+    }
+
+    @Override
+    public Sequence<Row> apply(
+        @Nullable Sequence<Row> input
+    )
+    {
+      return Sequences.limit(input, limit);
+    }
+  }
+
+  private static class SortingFn implements Function<Sequence<Row>, Sequence<Row>>
+  {
+    private final Ordering<Row> ordering;
+
+    public SortingFn(Ordering<Row> ordering) {this.ordering = ordering;}
+
+    @Override
+    public Sequence<Row> apply(@Nullable Sequence<Row> input)
+    {
+      return Sequences.sort(input, ordering);
+    }
+  }
+
+  private static class TopNFunction implements Function<Sequence<Row>, Sequence<Row>>
+  {
+    private final TopNSorter<Row> sorter;
+    private final int limit;
+
+    public TopNFunction(Ordering<Row> ordering, int limit)
+    {
+      this.limit = limit;
+
+      this.sorter = new TopNSorter<Row>(ordering);
+    }
+
+    @Override
+    public Sequence<Row> apply(
+        @Nullable Sequence<Row> input
+    )
+    {
+      final ArrayList<Row> materializedList = Sequences.toList(input, Lists.<Row>newArrayList());
+      return Sequences.simple(sorter.toTopN(materializedList, limit));
+    }
+  }
 }

client/src/main/java/com/metamx/druid/query/group/orderby/LimitSpec.java

@@ -17,7 +17,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-package com.metamx.druid.query.group.limit;
+package com.metamx.druid.query.group.orderby;
 
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;

client/src/main/java/com/metamx/druid/query/group/orderby/NoopLimitSpec.java

@@ -1,4 +1,4 @@
-package com.metamx.druid.query.group.limit;
+package com.metamx.druid.query.group.orderby;
 
 import com.google.common.base.Function;
 import com.google.common.base.Functions;

client/src/main/java/com/metamx/druid/query/group/orderby/OrderByColumnSpec.java

@@ -1,12 +1,17 @@
-package com.metamx.druid.query.group.limit;
+package com.metamx.druid.query.group.orderby;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
 import com.metamx.common.IAE;
 import com.metamx.common.ISE;
 
+import javax.annotation.Nullable;
+import java.util.Arrays;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -52,6 +57,46 @@ public class OrderByColumnSpec
     }
   }
 
+  public static OrderByColumnSpec asc(String dimension)
+  {
+    return new OrderByColumnSpec(dimension, Direction.ASCENDING);
+  }
+
+  public static List<OrderByColumnSpec> ascending(String... dimension)
+  {
+    return Lists.transform(
+        Arrays.asList(dimension),
+        new Function<String, OrderByColumnSpec>()
+        {
+          @Override
+          public OrderByColumnSpec apply(@Nullable String input)
+          {
+            return asc(input);
+          }
+        }
+    );
+  }
+
+  public static OrderByColumnSpec desc(String dimension)
+  {
+    return new OrderByColumnSpec(dimension, Direction.DESCENDING);
+  }
+
+  public static List<OrderByColumnSpec> descending(String... dimension)
+  {
+    return Lists.transform(
+        Arrays.asList(dimension),
+        new Function<String, OrderByColumnSpec>()
+        {
+          @Override
+          public OrderByColumnSpec apply(@Nullable String input)
+          {
+            return desc(input);
+          }
+        }
+    );
+  }
+
   public OrderByColumnSpec(
       String dimension,
       Direction direction

client/src/main/java/com/metamx/druid/query/group/orderby/OrderedPriorityQueueItems.java

@@ -0,0 +1,43 @@
+package com.metamx.druid.query.group.orderby;
+
+import com.google.common.collect.MinMaxPriorityQueue;
+
+import java.util.Iterator;
+
+/**
+ * Utility class that supports iterating a priority queue in sorted order.
+ */
+class OrderedPriorityQueueItems<T> implements Iterable<T>
+{
+  private MinMaxPriorityQueue<T> rows;
+
+  public OrderedPriorityQueueItems(MinMaxPriorityQueue<T> rows)
+  {
+    this.rows = rows;
+  }
+
+  @Override
+  public Iterator<T> iterator()
+  {
+    return new Iterator<T>() {
+
+      @Override
+      public boolean hasNext()
+      {
+        return !rows.isEmpty();
+      }
+
+      @Override
+      public T next()
+      {
+        return rows.poll();
+      }
+
+      @Override
+      public void remove()
+      {
+        throw new UnsupportedOperationException("Can't remove any item from an intermediary heap for orderBy/limit");
+      }
+    };
+  }
+}

client/src/main/java/com/metamx/druid/query/group/orderby/TopNSorter.java

@@ -0,0 +1,40 @@
+package com.metamx.druid.query.group.orderby;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.MinMaxPriorityQueue;
+import com.google.common.collect.Ordering;
+
+/**
+ * A utility class that sorts a list of comparable items in the given order, and keeps only the
+ * top N sorted items.
+ */
+public class TopNSorter<T>
+{
+  private Ordering<T> ordering;
+
+  /**
+   * Constructs a sorter that will sort items with given ordering.
+   * @param ordering the order that this sorter instance will use for sorting
+   */
+  public TopNSorter(Ordering<T> ordering)
+  {
+    this.ordering = ordering;
+  }
+
+  /**
+   * Sorts a list of rows and retain the top n items
+   * @param items the collections of items to be sorted
+   * @param n the number of items to be retained
+   * @return Top n items that are sorted in the order specified when this instance is constructed.
+   */
+  public Iterable<T> toTopN(Iterable<T> items, int n)
+  {
+    if(n <= 0) {
+      return ImmutableList.of();
+    }
+
+    MinMaxPriorityQueue<T> queue = MinMaxPriorityQueue.orderedBy(ordering).maximumSize(n).create(items);
+
+    return new OrderedPriorityQueueItems<T>(queue);
+  }
+}

client/src/test/java/com/metamx/druid/query/group/having/HavingSpecTest.java

@@ -0,0 +1,227 @@
+package com.metamx.druid.query.group.having;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.metamx.druid.input.MapBasedInputRow;
+import com.metamx.druid.input.Row;
+import com.metamx.druid.jackson.DefaultObjectMapper;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+
+public class HavingSpecTest
+{
+  private static final Row ROW = new MapBasedInputRow(0, new ArrayList<String>(), ImmutableMap.of("metric", (Object)Float.valueOf(10)));
+
+  @Test
+  public void testHavingClauseSerde() throws Exception {
+    List<HavingSpec> havings = Arrays.asList(
+      new GreaterThanHavingSpec("agg", Double.valueOf(1.3)),
+      new OrHavingSpec(
+        Arrays.asList(
+          new LessThanHavingSpec("lessAgg", Long.valueOf(1L)),
+          new NotHavingSpec(new EqualToHavingSpec("equalAgg", Double.valueOf(2)))
+        )
+      )
+    );
+
+    HavingSpec andHavingSpec = new AndHavingSpec(havings);
+
+    Map<String, Object> notMap = ImmutableMap.<String, Object>of(
+        "type", "not",
+        "havingSpec", ImmutableMap.of("type", "equalTo", "aggregation", "equalAgg", "value", 2.0)
+    );
+
+    Map<String, Object> lessMap = ImmutableMap.<String, Object>of(
+        "type", "lessThan",
+        "aggregation", "lessAgg",
+        "value", 1
+    );
+
+    Map<String, Object> greaterMap = ImmutableMap.<String, Object>of(
+        "type", "greaterThan",
+        "aggregation", "agg",
+        "value", 1.3
+    );
+
+    Map<String, Object> orMap = ImmutableMap.<String, Object>of(
+        "type", "or",
+        "havingSpecs", ImmutableList.of(lessMap, notMap)
+    );
+
+    Map<String, Object> payloadMap = ImmutableMap.<String, Object>of(
+        "type", "and",
+        "havingSpecs", ImmutableList.of(greaterMap, orMap)
+    );
+
+    ObjectMapper mapper = new DefaultObjectMapper();
+    assertEquals(andHavingSpec,  mapper.convertValue(payloadMap, AndHavingSpec.class));
+  }
+
+  @Test
+  public void testGreaterThanHavingSpec() {
+    GreaterThanHavingSpec spec = new GreaterThanHavingSpec("metric", 10.003);
+    assertFalse(spec.eval(ROW));
+
+    spec = new GreaterThanHavingSpec("metric", 10);
+    assertFalse(spec.eval(ROW));
+
+    spec = new GreaterThanHavingSpec("metric", 9);
+    assertTrue(spec.eval(ROW));
+  }
+
+  private MapBasedInputRow makeRow(long ts, String dim, int value)
+  {
+    List<String> dimensions = Lists.newArrayList(dim);
+    Map<String, Object> metrics = ImmutableMap.of("metric", (Object) Float.valueOf(value));
+
+    return new MapBasedInputRow(ts, dimensions, metrics);
+  }
+
+  @Test
+  public void testLessThanHavingSpec() {
+    LessThanHavingSpec spec = new LessThanHavingSpec("metric", 10);
+    assertFalse(spec.eval(ROW));
+
+    spec = new LessThanHavingSpec("metric", 11);
+    assertTrue(spec.eval(ROW));
+
+    spec = new LessThanHavingSpec("metric", 9);
+    assertFalse(spec.eval(ROW));
+  }
+
+  @Test
+  public void testEqualHavingSpec() {
+    EqualToHavingSpec spec = new EqualToHavingSpec("metric", 10);
+    assertTrue(spec.eval(ROW));
+
+    spec = new EqualToHavingSpec("metric", 9);
+    assertFalse(spec.eval(ROW));
+
+    spec = new EqualToHavingSpec("metric", 11);
+    assertFalse(spec.eval(ROW));
+  }
+
+  private static class CountingHavingSpec implements HavingSpec {
+
+    private final AtomicInteger counter;
+    private final boolean value;
+    private CountingHavingSpec(AtomicInteger counter, boolean value)
+    {
+      this.counter = counter;
+      this.value = value;
+    }
+
+    @Override
+    public boolean eval(Row row)
+    {
+      counter.incrementAndGet();
+      return value;
+    }
+  }
+
+  @Test
+  public void testAndHavingSpecShouldSupportShortcutEvaluation () {
+    AtomicInteger counter = new AtomicInteger(0);
+    AndHavingSpec spec = new AndHavingSpec(ImmutableList.of(
+      (HavingSpec)new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, false)
+    ));
+
+    spec.eval(ROW);
+
+    assertEquals(2, counter.get());
+  }
+
+  @Test
+  public void testAndHavingSpec () {
+    AtomicInteger counter = new AtomicInteger(0);
+    AndHavingSpec spec = new AndHavingSpec(ImmutableList.of(
+      (HavingSpec)new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true)
+    ));
+
+    spec.eval(ROW);
+
+    assertEquals(4, counter.get());
+
+    counter.set(0);
+    spec = new AndHavingSpec(ImmutableList.of(
+      (HavingSpec)new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true)
+    ));
+
+    spec.eval(ROW);
+
+    assertEquals(1, counter.get());
+  }
+
+  @Test
+  public void testOrHavingSpecSupportsShortcutEvaluation() {
+    AtomicInteger counter = new AtomicInteger(0);
+    OrHavingSpec spec = new OrHavingSpec(ImmutableList.of(
+      (HavingSpec)new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, true),
+      new CountingHavingSpec(counter, false)
+    ));
+
+    spec.eval(ROW);
+
+    assertEquals(1, counter.get());
+  }
+
+  @Test
+  public void testOrHavingSpec () {
+    AtomicInteger counter = new AtomicInteger(0);
+    OrHavingSpec spec = new OrHavingSpec(ImmutableList.of(
+      (HavingSpec)new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, false)
+    ));
+
+    spec.eval(ROW);
+
+    assertEquals(4, counter.get());
+
+    counter.set(0);
+    spec = new OrHavingSpec(ImmutableList.of(
+      (HavingSpec)new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, false),
+      new CountingHavingSpec(counter, true)
+    ));
+
+    spec.eval(ROW);
+
+    assertEquals(4, counter.get());
+  }
+
+  @Test
+  public void testNotHavingSepc() {
+    NotHavingSpec spec = new NotHavingSpec(HavingSpec.NEVER);
+    assertTrue(spec.eval(ROW));
+
+    spec = new NotHavingSpec(HavingSpec.ALWAYS);
+    assertFalse(spec.eval(ROW));
+
+  }
+}

client/src/test/java/com/metamx/druid/query/group/orderby/TopNSorterTest.java

@@ -0,0 +1,79 @@
+package com.metamx.druid.query.group.orderby;
+
+import com.google.common.base.Splitter;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Ordering;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+
+
+@RunWith(Parameterized.class)
+public class TopNSorterTest
+{
+  private static final long SEED = 2L;
+  private static final Ordering<String> ASC = Ordering.natural();
+  private static final Ordering<String> DESC = Ordering.natural().reverse();
+
+  private static final List<String> EMPTY = Collections.EMPTY_LIST;
+  private static final List<String> SINGLE = Lists.newArrayList("a");
+  private static final List<String> RAW_ASC = Lists.newArrayList(Splitter.fixedLength(1).split("abcdefghijk"));
+  private static final List<String> RAW_DESC = Lists.newArrayList(Splitter.fixedLength(1).split("kjihgfedcba"));
+
+  private Ordering<String> ordering;
+  private List<String> rawInput;
+  private int limit;
+
+  @Parameterized.Parameters
+  public static Collection<Object[]> makeTestData(){
+    Object[][] data = new Object[][] {
+      { ASC, RAW_ASC, RAW_ASC.size() - 2},
+      { ASC, RAW_ASC, RAW_ASC.size()},
+      { ASC, RAW_ASC, RAW_ASC.size() + 2},
+      { ASC, RAW_ASC, 0},
+      { ASC, SINGLE, 0},
+      { ASC, SINGLE, 1},
+      { ASC, SINGLE, 2},
+      { ASC, SINGLE, 3},
+      { ASC, EMPTY, 0},
+      { ASC, EMPTY, 1},
+      { DESC, RAW_DESC, RAW_DESC.size() - 2},
+      { DESC, RAW_DESC, RAW_DESC.size()},
+      { DESC, RAW_DESC, RAW_DESC.size() + 2},
+      { DESC, RAW_DESC, 0},
+      { DESC, RAW_DESC, 0},
+      { DESC, SINGLE, 1},
+      { DESC, SINGLE, 2},
+      { DESC, SINGLE, 3},
+      { DESC, EMPTY, 0},
+      { DESC, EMPTY, 1},
+    };
+
+    return Arrays.asList(data);
+  }
+
+  public TopNSorterTest(Ordering<String> ordering, List<String> rawInput, int limit){
+    this.ordering = ordering;
+    this.rawInput = rawInput;
+    this.limit = limit;
+  }
+
+  @Test
+  public void testOrderByWithLimit()
+  {
+    List<String> expected = rawInput.subList(0, Math.min(limit, rawInput.size()));
+    List<String> inputs = Lists.newArrayList(rawInput);
+    Collections.shuffle(inputs, new Random(2));
+
+    Iterable<String> result = new TopNSorter<String>(ordering).toTopN(inputs, limit);
+
+    Assert.assertEquals(expected, Lists.newArrayList(result));
+  }
+}

indexer/pom.xml

@@ -120,12 +120,6 @@
                             <outputFile>
                                 ${project.build.directory}/${project.artifactId}-${project.version}-selfcontained.jar
                             </outputFile>
-                            <relocations>
-                                <relocation>
-                                    <pattern>org.codehaus.jackson</pattern>
-                                    <shadedPattern>druid.org.codehaus.jackson</shadedPattern>
-                                </relocation>
-                            </relocations>
                         </configuration>
                     </execution>
                 </executions>

pom.xml

@@ -209,16 +209,6 @@
                 <artifactId>jackson-jaxrs-json-provider</artifactId>
                 <version>2.1.4</version>
             </dependency>
-            <dependency>
-                <groupId>org.codehaus.jackson</groupId>
-                <artifactId>jackson-core-asl</artifactId>
-                <version>1.9.11</version>
-            </dependency>
-            <dependency>
-                <groupId>org.codehaus.jackson</groupId>
-                <artifactId>jackson-mapper-asl</artifactId>
-                <version>1.9.11</version>
-            </dependency>
             <dependency>
                 <groupId>javax.inject</groupId>
                 <artifactId>javax.inject</artifactId>

server/src/test/java/com/metamx/druid/TestHelper.java

@@ -69,7 +69,7 @@ public class TestHelper
 
       assertResult(failMsg, expectedNext, next);
       assertResult(
-          String.format("%sSecond iterator bad, multiple calls to iterator() should be safe", failMsg),
+          String.format("%s: Second iterator bad, multiple calls to iterator() should be safe", failMsg),
           expectedNext,
           next2
       );
@@ -77,20 +77,20 @@ public class TestHelper
 
     if (resultsIter.hasNext()) {
       Assert.fail(
-          String.format("%sExpected resultsIter to be exhausted, next element was %s", failMsg, resultsIter.next())
+          String.format("%s: Expected resultsIter to be exhausted, next element was %s", failMsg, resultsIter.next())
       );
     }
 
     if (resultsIter2.hasNext()) {
       Assert.fail(
-          String.format("%sExpected resultsIter2 to be exhausted, next element was %s", failMsg, resultsIter.next())
+          String.format("%s: Expected resultsIter2 to be exhausted, next element was %s", failMsg, resultsIter.next())
       );
     }
 
     if (expectedResultsIter.hasNext()) {
       Assert.fail(
           String.format(
-              "%sExpected expectedResultsIter to be exhausted, next element was %s", failMsg, expectedResultsIter.next()
+              "%s: Expected expectedResultsIter to be exhausted, next element was %s", failMsg, expectedResultsIter.next()
           )
       );
     }
@@ -109,7 +109,7 @@ public class TestHelper
 
       Assert.assertEquals(failMsg, expectedNext, next);
       Assert.assertEquals(
-          String.format("%sSecond iterator bad, multiple calls to iterator() should be safe", failMsg),
+          String.format("%s: Second iterator bad, multiple calls to iterator() should be safe", failMsg),
           expectedNext,
           next2
       );
@@ -117,20 +117,20 @@ public class TestHelper
 
     if (resultsIter.hasNext()) {
       Assert.fail(
-          String.format("%sExpected resultsIter to be exhausted, next element was %s", failMsg, resultsIter.next())
+          String.format("%s: Expected resultsIter to be exhausted, next element was %s", failMsg, resultsIter.next())
       );
     }
 
     if (resultsIter2.hasNext()) {
       Assert.fail(
-          String.format("%sExpected resultsIter2 to be exhausted, next element was %s", failMsg, resultsIter.next())
+          String.format("%s: Expected resultsIter2 to be exhausted, next element was %s", failMsg, resultsIter.next())
       );
     }
 
     if (expectedResultsIter.hasNext()) {
       Assert.fail(
           String.format(
-              "%sExpected expectedResultsIter to be exhausted, next element was %s", failMsg, expectedResultsIter.next()
+              "%s: Expected expectedResultsIter to be exhausted, next element was %s", failMsg, expectedResultsIter.next()
           )
       );
     }

server/src/test/java/com/metamx/druid/query/group/GroupByQueryRunnerTest.java

@@ -22,9 +22,12 @@ package com.metamx.druid.query.group;
 import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Supplier;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Ordering;
+import com.metamx.common.guava.Accumulator;
 import com.metamx.common.guava.Sequence;
 import com.metamx.common.guava.Sequences;
 import com.metamx.druid.PeriodGranularity;
@@ -41,7 +44,12 @@ import com.metamx.druid.query.QueryRunner;
 import com.metamx.druid.query.QueryRunnerTestHelper;
 import com.metamx.druid.query.dimension.DefaultDimensionSpec;
 import com.metamx.druid.query.dimension.DimensionSpec;
-import com.metamx.druid.query.group.limit.OrderByColumnSpec;
+import com.metamx.druid.query.group.having.EqualToHavingSpec;
+import com.metamx.druid.query.group.having.GreaterThanHavingSpec;
+import com.metamx.druid.query.group.having.OrHavingSpec;
+import com.metamx.druid.query.group.orderby.DefaultLimitSpec;
+import com.metamx.druid.query.group.orderby.LimitSpec;
+import com.metamx.druid.query.group.orderby.OrderByColumnSpec;
 import com.metamx.druid.query.segment.MultipleIntervalSegmentSpec;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
@@ -56,6 +64,7 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
@@ -89,7 +98,9 @@ public class GroupByQueryRunnerTest
                 }
             )
         ),
-                    new GroupByQueryRunnerFactoryConfig(){}
+        new GroupByQueryRunnerFactoryConfig()
+        {
+        }
     );
 
     return Lists.newArrayList(
@@ -106,13 +117,15 @@ public class GroupByQueryRunnerTest
     );
   }
 
-  public GroupByQueryRunnerTest(GroupByQueryRunnerFactory factory, QueryRunner runner) {
+  public GroupByQueryRunnerTest(GroupByQueryRunnerFactory factory, QueryRunner runner)
+  {
     this.factory = factory;
     this.runner = runner;
   }
 
   @Test
-  public void testGroupBy() {
+  public void testGroupBy()
+  {
     GroupByQuery query = GroupByQuery
         .builder()
         .setDataSource(QueryRunnerTestHelper.dataSource)
@@ -155,7 +168,8 @@ public class GroupByQueryRunnerTest
   }
 
   @Test
-  public void testGroupByWithTimeZone() {
+  public void testGroupByWithTimeZone()
+  {
     DateTimeZone tz = DateTimeZone.forID("America/Los_Angeles");
 
     GroupByQuery query = GroupByQuery.builder()
@@ -218,7 +232,8 @@ public class GroupByQueryRunnerTest
   }
 
   @Test
-  public void testMergeResults() {
+  public void testMergeResults()
+  {
     GroupByQuery.Builder builder = GroupByQuery
         .builder()
         .setDataSource(QueryRunnerTestHelper.dataSource)
@@ -282,7 +297,180 @@ public class GroupByQueryRunnerTest
 
     TestHelper.assertExpectedObjects(allGranExpectedResults, runner.run(allGranQuery), "direct");
     TestHelper.assertExpectedObjects(allGranExpectedResults, mergedRunner.run(allGranQuery), "merged");
+  }
 
+  @Test
+  public void testMergeResultsWithLimit()
+  {
+    for (int limit = 1; limit < 20; ++limit) {
+      doTestMergeResultsWithValidLimit(limit);
+    }
+  }
+
+  private void doTestMergeResultsWithValidLimit(final int limit)
+  {
+    GroupByQuery.Builder builder = GroupByQuery
+        .builder()
+        .setDataSource(QueryRunnerTestHelper.dataSource)
+        .setInterval("2011-04-02/2011-04-04")
+        .setDimensions(Lists.<DimensionSpec>newArrayList(new DefaultDimensionSpec("quality", "alias")))
+        .setAggregatorSpecs(
+            Arrays.<AggregatorFactory>asList(
+                QueryRunnerTestHelper.rowsCount,
+                new LongSumAggregatorFactory("idx", "index")
+            )
+        )
+        .setGranularity(new PeriodGranularity(new Period("P1M"), null, null))
+        .setLimit(Integer.valueOf(limit));
+
+    final GroupByQuery fullQuery = builder.build();
+
+    List<Row> expectedResults = Arrays.asList(
+        createExpectedRow("2011-04-01", "alias", "automotive", "rows", 2L, "idx", 269L),
+        createExpectedRow("2011-04-01", "alias", "business", "rows", 2L, "idx", 217L),
+        createExpectedRow("2011-04-01", "alias", "entertainment", "rows", 2L, "idx", 319L),
+        createExpectedRow("2011-04-01", "alias", "health", "rows", 2L, "idx", 216L),
+        createExpectedRow("2011-04-01", "alias", "mezzanine", "rows", 6L, "idx", 4420L),
+        createExpectedRow("2011-04-01", "alias", "news", "rows", 2L, "idx", 221L),
+        createExpectedRow("2011-04-01", "alias", "premium", "rows", 6L, "idx", 4416L),
+        createExpectedRow("2011-04-01", "alias", "technology", "rows", 2L, "idx", 177L),
+        createExpectedRow("2011-04-01", "alias", "travel", "rows", 2L, "idx", 243L)
+    );
+
+    QueryRunner<Row> mergeRunner = new GroupByQueryQueryToolChest().mergeResults(runner);
+
+    mergeRunner.run(fullQuery).accumulate(null, new Accumulator<Object, Row>()
+    {
+      @Override
+      public Object accumulate(Object o, Row row)
+      {
+        System.out.printf("%d: %s%n", limit, row);
+        return null;
+      }
+    });
+
+    TestHelper.assertExpectedObjects(
+        Iterables.limit(expectedResults, limit), mergeRunner.run(fullQuery), String.format("limit: %d", limit)
+    );
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testMergeResultsWithNegativeLimit()
+  {
+    GroupByQuery.Builder builder = GroupByQuery
+        .builder()
+        .setDataSource(QueryRunnerTestHelper.dataSource)
+        .setInterval("2011-04-02/2011-04-04")
+        .setDimensions(Lists.<DimensionSpec>newArrayList(new DefaultDimensionSpec("quality", "alias")))
+        .setAggregatorSpecs(
+            Arrays.<AggregatorFactory>asList(
+                QueryRunnerTestHelper.rowsCount,
+                new LongSumAggregatorFactory("idx", "index")
+            )
+        )
+        .setGranularity(new PeriodGranularity(new Period("P1M"), null, null))
+        .setLimit(Integer.valueOf(-1));
+
+    builder.build();
+  }
+
+  @Test
+  public void testMergeResultsWithOrderBy()
+  {
+    LimitSpec[] orderBySpecs = new LimitSpec[]{
+        new DefaultLimitSpec(OrderByColumnSpec.ascending("idx"), null),
+        new DefaultLimitSpec(OrderByColumnSpec.ascending("rows", "idx"), null),
+        new DefaultLimitSpec(OrderByColumnSpec.descending("idx"), null),
+        new DefaultLimitSpec(OrderByColumnSpec.descending("rows", "idx"), null),
+    };
+
+    final Comparator<Row> idxComparator =
+        new Comparator<Row>()
+        {
+          @Override
+          public int compare(Row o1, Row o2)
+          {
+            return Float.compare(o1.getFloatMetric("idx"), o2.getFloatMetric("idx"));
+          }
+        };
+
+    Comparator<Row> rowsIdxComparator =
+        new Comparator<Row>()
+        {
+
+          @Override
+          public int compare(Row o1, Row o2)
+          {
+            int value = Float.compare(o1.getFloatMetric("rows"), o2.getFloatMetric("rows"));
+            if (value != 0) {
+              return value;
+            }
+
+            return idxComparator.compare(o1, o2);
+          }
+        };
+
+    List<Row> allResults = Arrays.asList(
+        createExpectedRow("2011-04-01", "alias", "automotive", "rows", 2L, "idx", 269L),
+        createExpectedRow("2011-04-01", "alias", "business", "rows", 2L, "idx", 217L),
+        createExpectedRow("2011-04-01", "alias", "entertainment", "rows", 2L, "idx", 319L),
+        createExpectedRow("2011-04-01", "alias", "health", "rows", 2L, "idx", 216L),
+        createExpectedRow("2011-04-01", "alias", "mezzanine", "rows", 6L, "idx", 4420L),
+        createExpectedRow("2011-04-01", "alias", "news", "rows", 2L, "idx", 221L),
+        createExpectedRow("2011-04-01", "alias", "premium", "rows", 6L, "idx", 4416L),
+        createExpectedRow("2011-04-01", "alias", "technology", "rows", 2L, "idx", 177L),
+        createExpectedRow("2011-04-01", "alias", "travel", "rows", 2L, "idx", 243L)
+    );
+
+    List<List<Row>> expectedResults = Lists.newArrayList(
+        Ordering.from(idxComparator).sortedCopy(allResults),
+        Ordering.from(rowsIdxComparator).sortedCopy(allResults),
+        Ordering.from(idxComparator).reverse().sortedCopy(allResults),
+        Ordering.from(rowsIdxComparator).reverse().sortedCopy(allResults)
+    );
+
+    for (int i = 0; i < orderBySpecs.length; ++i) {
+      doTestMergeResultsWithOrderBy(orderBySpecs[i], expectedResults.get(i));
+    }
+  }
+
+  private void doTestMergeResultsWithOrderBy(LimitSpec orderBySpec, List<Row> expectedResults)
+  {
+    GroupByQuery.Builder builder = GroupByQuery
+        .builder()
+        .setDataSource(QueryRunnerTestHelper.dataSource)
+        .setInterval("2011-04-02/2011-04-04")
+        .setDimensions(Lists.<DimensionSpec>newArrayList(new DefaultDimensionSpec("quality", "alias")))
+        .setAggregatorSpecs(
+            Arrays.<AggregatorFactory>asList(
+                QueryRunnerTestHelper.rowsCount,
+                new LongSumAggregatorFactory("idx", "index")
+            )
+        )
+        .setGranularity(new PeriodGranularity(new Period("P1M"), null, null))
+        .setLimitSpec(orderBySpec);
+
+    final GroupByQuery fullQuery = builder.build();
+
+    QueryRunner mergedRunner = new GroupByQueryQueryToolChest().mergeResults(
+        new QueryRunner<Row>()
+        {
+          @Override
+          public Sequence run(Query<Row> query)
+          {
+            // simulate two daily segments
+            final Query query1 = query.withQuerySegmentSpec(
+                new MultipleIntervalSegmentSpec(Lists.newArrayList(new Interval("2011-04-02/2011-04-03")))
+            );
+            final Query query2 = query.withQuerySegmentSpec(
+                new MultipleIntervalSegmentSpec(Lists.newArrayList(new Interval("2011-04-03/2011-04-04")))
+            );
+            return Sequences.concat(runner.run(query1), runner.run(query2));
+          }
+        }
+    );
+
+    TestHelper.assertExpectedObjects(expectedResults, mergedRunner.run(fullQuery), "merged");
   }
 
   @Test
@@ -403,6 +591,59 @@ public class GroupByQueryRunnerTest
     );
   }
 
+  @Test
+  public void testHavingSpec()
+  {
+    List<Row> expectedResults = Arrays.asList(
+        createExpectedRow("2011-04-01", "alias", "business", "rows", 2L, "idx", 217L),
+        createExpectedRow("2011-04-01", "alias", "mezzanine", "rows", 6L, "idx", 4420L),
+        createExpectedRow("2011-04-01", "alias", "premium", "rows", 6L, "idx", 4416L)
+    );
+
+    GroupByQuery.Builder builder = GroupByQuery
+        .builder()
+        .setDataSource(QueryRunnerTestHelper.dataSource)
+        .setInterval("2011-04-02/2011-04-04")
+        .setDimensions(Lists.<DimensionSpec>newArrayList(new DefaultDimensionSpec("quality", "alias")))
+        .setAggregatorSpecs(
+            Arrays.<AggregatorFactory>asList(
+                QueryRunnerTestHelper.rowsCount,
+                new LongSumAggregatorFactory("idx", "index")
+            )
+        )
+        .setGranularity(new PeriodGranularity(new Period("P1M"), null, null))
+        .setHavingSpec(
+            new OrHavingSpec(
+                ImmutableList.of(
+                    new GreaterThanHavingSpec("rows", 2L),
+                    new EqualToHavingSpec("idx", 217L)
+                )
+            )
+        );
+
+    final GroupByQuery fullQuery = builder.build();
+
+    QueryRunner mergedRunner = new GroupByQueryQueryToolChest().mergeResults(
+        new QueryRunner<Row>()
+        {
+          @Override
+          public Sequence run(Query<Row> query)
+          {
+            // simulate two daily segments
+            final Query query1 = query.withQuerySegmentSpec(
+                new MultipleIntervalSegmentSpec(Lists.newArrayList(new Interval("2011-04-02/2011-04-03")))
+            );
+            final Query query2 = query.withQuerySegmentSpec(
+                new MultipleIntervalSegmentSpec(Lists.newArrayList(new Interval("2011-04-03/2011-04-04")))
+            );
+            return Sequences.concat(runner.run(query1), runner.run(query2));
+          }
+        }
+    );
+
+    TestHelper.assertExpectedObjects(expectedResults, mergedRunner.run(fullQuery), "merged");
+  }
+
   private Row createExpectedRow(final String timestamp, Object... vals)
   {
     return createExpectedRow(new DateTime(timestamp), vals);
@@ -417,6 +658,6 @@ public class GroupByQueryRunnerTest
       theVals.put(vals[i].toString(), vals[i + 1]);
     }
 
-    return new MapBasedRow(timestamp, theVals);
+    return new MapBasedRow(new DateTime(timestamp), theVals);
   }
 }