Add StorageAdapter#getColumnTypeName, and various SegmentMetadataQuery adjustments.

SegmentMetadataQuery stuff:

- Simplify implementation of SegmentAnalyzer.
- Fix type names for realtime complex columns; this used to try to merge a nice type
  name (like "hyperUnique") from mmapped segments with the word "COMPLEX" from incremental
  index segments, leading to a merge failure. Now it always uses the nice name.
- Add hasMultipleValues to ColumnAnalysis.
- Add tests for both mmapped and incremental index segments.
- Update docs to include errorMessage.

docs/content/querying/segmentmetadataquery.md

@@ -39,10 +39,10 @@ The format of the result is:
   "id" : "some_id",
   "intervals" : [ "2013-05-13T00:00:00.000Z/2013-05-14T00:00:00.000Z" ],
   "columns" : {
-    "__time" : { "type" : "LONG", "size" : 407240380, "cardinality" : null },
+    "__time" : { "type" : "LONG", "hasMultipleValues" : false, "size" : 407240380, "cardinality" : null, "errorMessage" : null },
-    "dim1" : { "type" : "STRING", "size" : 100000, "cardinality" : 1944 },
+    "dim1" : { "type" : "STRING", "hasMultipleValues" : false, "size" : 100000, "cardinality" : 1944, "errorMessage" : null },
-    "dim2" : { "type" : "STRING", "size" : 100000, "cardinality" : 1504 },
+    "dim2" : { "type" : "STRING", "hasMultipleValues" : true, "size" : 100000, "cardinality" : 1504, "errorMessage" : null },
-    "metric1" : { "type" : "FLOAT", "size" : 100000, "cardinality" : null }
+    "metric1" : { "type" : "FLOAT", "hasMultipleValues" : false, "size" : 100000, "cardinality" : null, "errorMessage" : null }
   },
   "size" : 300000,
   "numRows" : 5000000
@@ -53,6 +53,9 @@ Dimension columns will have type `STRING`.
 Metric columns will have type `FLOAT` or `LONG` or name of the underlying complex type such as `hyperUnique` in case of COMPLEX metric.
 Timestamp column will have type `LONG`.
 
+If the `errorMessage` field is non-null, you should not trust the other fields in the response. Their contents are
+undefined.
+
 Only columns which are dimensions (ie, have type `STRING`) will have any cardinality. Rest of the columns (timestamp and metric columns) will show cardinality as `null`.
 
 ### intervals

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

@@ -22,28 +22,29 @@ package io.druid.query.metadata;
 import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Iterables;
-import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
 import com.google.common.primitives.Longs;
 import com.metamx.common.StringUtils;
 import com.metamx.common.logger.Logger;
 import io.druid.query.metadata.metadata.ColumnAnalysis;
 import io.druid.query.metadata.metadata.SegmentMetadataQuery;
 import io.druid.segment.QueryableIndex;
+import io.druid.segment.Segment;
 import io.druid.segment.StorageAdapter;
 import io.druid.segment.column.BitmapIndex;
 import io.druid.segment.column.Column;
 import io.druid.segment.column.ColumnCapabilities;
+import io.druid.segment.column.ColumnCapabilitiesImpl;
 import io.druid.segment.column.ComplexColumn;
 import io.druid.segment.column.ValueType;
-import io.druid.segment.data.Indexed;
 import io.druid.segment.serde.ComplexMetricSerde;
 import io.druid.segment.serde.ComplexMetrics;
 
-import java.util.Collections;
+import javax.annotation.Nullable;
 import java.util.EnumSet;
-import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 public class SegmentAnalyzer
 {
@@ -59,33 +60,54 @@ public class SegmentAnalyzer
    */
   private static final int NUM_BYTES_IN_TEXT_FLOAT = 8;
 
-  public Map<String, ColumnAnalysis> analyze(
+  private final EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes;
-      QueryableIndex index,
+
-      EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes
+  public SegmentAnalyzer(EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
-  )
   {
-    Preconditions.checkNotNull(index, "Index cannot be null");
+    this.analysisTypes = analysisTypes;
+  }
+
+  public int numRows(Segment segment)
+  {
+    return Preconditions.checkNotNull(segment, "segment").asStorageAdapter().getNumRows();
+  }
+
+  public Map<String, ColumnAnalysis> analyze(Segment segment)
+  {
+    Preconditions.checkNotNull(segment, "segment");
+
+    // index is null for incremental-index-based segments, but storageAdapter is always available
+    final QueryableIndex index = segment.asQueryableIndex();
+    final StorageAdapter storageAdapter = segment.asStorageAdapter();
+
+    // get length and column names from storageAdapter
+    final int length = storageAdapter.getNumRows();
+    final Set<String> columnNames = Sets.newHashSet();
+    Iterables.addAll(columnNames, storageAdapter.getAvailableDimensions());
+    Iterables.addAll(columnNames, storageAdapter.getAvailableMetrics());
 
     Map<String, ColumnAnalysis> columns = Maps.newTreeMap();
 
-    for (String columnName : index.getColumnNames()) {
+    for (String columnName : columnNames) {
-      final Column column = index.getColumn(columnName);
+      final Column column = index == null ? null : index.getColumn(columnName);
-      final ColumnCapabilities capabilities = column.getCapabilities();
+      final ColumnCapabilities capabilities = column != null
+                                              ? column.getCapabilities()
+                                              : storageAdapter.getColumnCapabilities(columnName);
 
       final ColumnAnalysis analysis;
       final ValueType type = capabilities.getType();
       switch (type) {
         case LONG:
-          analysis = analyzeLongColumn(column, analysisTypes);
+          analysis = analyzeNumericColumn(capabilities, length, Longs.BYTES);
           break;
         case FLOAT:
-          analysis = analyzeFloatColumn(column, analysisTypes);
+          analysis = analyzeNumericColumn(capabilities, length, NUM_BYTES_IN_TEXT_FLOAT);
           break;
         case STRING:
-          analysis = analyzeStringColumn(column, analysisTypes);
+          analysis = analyzeStringColumn(capabilities, column, storageAdapter.getDimensionCardinality(columnName));
           break;
         case COMPLEX:
-          analysis = analyzeComplexColumn(column, analysisTypes);
+          analysis = analyzeComplexColumn(capabilities, column, storageAdapter.getColumnTypeName(columnName));
           break;
         default:
           log.warn("Unknown column type[%s].", type);
@@ -95,121 +117,72 @@ public class SegmentAnalyzer
       columns.put(columnName, analysis);
     }
 
+    // Add time column too
+    ColumnCapabilities timeCapabilities = storageAdapter.getColumnCapabilities(Column.TIME_COLUMN_NAME);
+    if (timeCapabilities == null) {
+      timeCapabilities = new ColumnCapabilitiesImpl().setType(ValueType.LONG).setHasMultipleValues(false);
+    }
     columns.put(
         Column.TIME_COLUMN_NAME,
-        lengthBasedAnalysis(index.getColumn(Column.TIME_COLUMN_NAME), NUM_BYTES_IN_TIMESTAMP, analysisTypes)
+        analyzeNumericColumn(timeCapabilities, length, NUM_BYTES_IN_TIMESTAMP)
     );
 
     return columns;
   }
 
-  public Map<String, ColumnAnalysis> analyze(
+  public boolean analyzingSize()
-      StorageAdapter adapter,
+  {
-      EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes
+    return analysisTypes.contains(SegmentMetadataQuery.AnalysisType.SIZE);
+  }
+
+  public boolean analyzingCardinality()
+  {
+    return analysisTypes.contains(SegmentMetadataQuery.AnalysisType.CARDINALITY);
+  }
+
+  private ColumnAnalysis analyzeNumericColumn(
+      final ColumnCapabilities capabilities,
+      final int length,
+      final int sizePerRow
   )
   {
-    Preconditions.checkNotNull(adapter, "Adapter cannot be null");
+    long size = 0;
-    Map<String, ColumnAnalysis> columns = Maps.newTreeMap();
-    List<String> columnNames = getStorageAdapterColumnNames(adapter);
 
-    int numRows = adapter.getNumRows();
+    if (analyzingSize()) {
-    for (String columnName : columnNames) {
-      final ColumnCapabilities capabilities = adapter.getColumnCapabilities(columnName);
-      final ColumnAnalysis analysis;
-
-      /**
-       * StorageAdapter doesn't provide a way to get column values, so size is
-       * not calculated for STRING and COMPLEX columns.
-       */
-      ValueType capType = capabilities.getType();
-      switch (capType) {
-        case LONG:
-          analysis = lengthBasedAnalysisForAdapter(
-              analysisTypes,
-              capType.name(), capabilities,
-              numRows, Longs.BYTES
-          );
-          break;
-        case FLOAT:
-          analysis = lengthBasedAnalysisForAdapter(
-              analysisTypes,
-              capType.name(), capabilities,
-              numRows, NUM_BYTES_IN_TEXT_FLOAT
-          );
-          break;
-        case STRING:
-          analysis = new ColumnAnalysis(
-              capType.name(),
-              0,
-              analysisHasCardinality(analysisTypes) ? adapter.getDimensionCardinality(columnName) : 0,
-              null
-          );
-          break;
-        case COMPLEX:
-          analysis = new ColumnAnalysis(
-              capType.name(),
-              0,
-              null,
-              null
-          );
-          break;
-        default:
-          log.warn("Unknown column type[%s].", capType);
-          analysis = ColumnAnalysis.error(String.format("unknown_type_%s", capType));
-      }
-
-      columns.put(columnName, analysis);
-    }
-
-    columns.put(
-        Column.TIME_COLUMN_NAME,
-        lengthBasedAnalysisForAdapter(analysisTypes, ValueType.LONG.name(), null, numRows, NUM_BYTES_IN_TIMESTAMP)
-    );
-
-    return columns;
-  }
-
-
-  public ColumnAnalysis analyzeLongColumn(Column column, EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
-  {
-    return lengthBasedAnalysis(column, Longs.BYTES, analysisTypes);
-  }
-
-  public ColumnAnalysis analyzeFloatColumn(Column column, EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
-  {
-    return lengthBasedAnalysis(column, NUM_BYTES_IN_TEXT_FLOAT, analysisTypes);
-  }
-
-  private ColumnAnalysis lengthBasedAnalysis(
-      Column column,
-      final int numBytes,
-      EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes
-  )
-  {
-    final ColumnCapabilities capabilities = column.getCapabilities();
       if (capabilities.hasMultipleValues()) {
         return ColumnAnalysis.error("multi_value");
       }
 
-    int size = 0;
+      size = ((long) length) * sizePerRow;
-    if (analysisHasSize(analysisTypes)) {
-      size = column.getLength() * numBytes;
     }
 
-    return new ColumnAnalysis(capabilities.getType().name(), size, null, null);
+    return new ColumnAnalysis(
+        capabilities.getType().name(),
+        capabilities.hasMultipleValues(),
+        size,
+        null,
+        null
+    );
   }
 
-  public ColumnAnalysis analyzeStringColumn(Column column, EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
+  private ColumnAnalysis analyzeStringColumn(
+      final ColumnCapabilities capabilities,
+      @Nullable final Column column,
+      final int cardinality
+  )
   {
-    final ColumnCapabilities capabilities = column.getCapabilities();
-
-    if (capabilities.hasBitmapIndexes()) {
-      final BitmapIndex bitmapIndex = column.getBitmapIndex();
-
-      int cardinality = bitmapIndex.getCardinality();
     long size = 0;
 
-      if (analysisHasSize(analysisTypes)) {
+    if (column != null && analyzingSize()) {
+      if (!capabilities.hasBitmapIndexes()) {
+        return ColumnAnalysis.error("string_no_bitmap");
+      }
+
+      final BitmapIndex bitmapIndex = column.getBitmapIndex();
+      if (cardinality != bitmapIndex.getCardinality()) {
+        return ColumnAnalysis.error("bitmap_wrong_cardinality");
+      }
+
       for (int i = 0; i < cardinality; ++i) {
         String value = bitmapIndex.getValue(i);
         if (value != null) {
@@ -220,21 +193,24 @@ public class SegmentAnalyzer
 
     return new ColumnAnalysis(
         capabilities.getType().name(),
+        capabilities.hasMultipleValues(),
         size,
-          analysisHasCardinality(analysisTypes) ? cardinality : 0,
+        analyzingCardinality() ? cardinality : 0,
         null
     );
   }
 
-    return ColumnAnalysis.error("string_no_bitmap");
+  private ColumnAnalysis analyzeComplexColumn(
-  }
+      @Nullable final ColumnCapabilities capabilities,
-
+      @Nullable final Column column,
-  public ColumnAnalysis analyzeComplexColumn(Column column, EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
+      final String typeName
+  )
   {
-    final ColumnCapabilities capabilities = column.getCapabilities();
+    final ComplexColumn complexColumn = column != null ? column.getComplexColumn() : null;
-    final ComplexColumn complexColumn = column.getComplexColumn();
+    final boolean hasMultipleValues = capabilities != null && capabilities.hasMultipleValues();
+    long size = 0;
 
-    final String typeName = complexColumn.getTypeName();
+    if (analyzingSize() && complexColumn != null) {
       final ComplexMetricSerde serde = ComplexMetrics.getSerdeForType(typeName);
       if (serde == null) {
         return ColumnAnalysis.error(String.format("unknown_complex_%s", typeName));
@@ -242,54 +218,21 @@ public class SegmentAnalyzer
 
       final Function<Object, Long> inputSizeFn = serde.inputSizeFn();
       if (inputSizeFn == null) {
-      return new ColumnAnalysis(typeName, 0, null, null);
+        return new ColumnAnalysis(typeName, hasMultipleValues, 0, null, null);
       }
 
       final int length = column.getLength();
-    long size = 0;
-    if (analysisHasSize(analysisTypes)) {
       for (int i = 0; i < length; ++i) {
         size += inputSizeFn.apply(complexColumn.getRowValue(i));
       }
     }
 
-    return new ColumnAnalysis(typeName, size, null, null);
-  }
-
-  private List<String> getStorageAdapterColumnNames(StorageAdapter adapter)
-  {
-    Indexed<String> dims = adapter.getAvailableDimensions();
-    Iterable<String> metrics = adapter.getAvailableMetrics();
-    Iterable<String> columnNames = Iterables.concat(dims, metrics);
-    List<String> sortedColumnNames = Lists.newArrayList(columnNames);
-    Collections.sort(sortedColumnNames);
-    return sortedColumnNames;
-  }
-
-  private ColumnAnalysis lengthBasedAnalysisForAdapter(
-      EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes,
-      String type, ColumnCapabilities capabilities,
-      int numRows, final int numBytes
-  )
-  {
-    if (capabilities != null && capabilities.hasMultipleValues()) {
-      return ColumnAnalysis.error("multi_value");
-    }
     return new ColumnAnalysis(
-        type,
+        typeName,
-        analysisHasSize(analysisTypes) ? numRows * numBytes : 0,
+        hasMultipleValues,
+        size,
         null,
         null
     );
   }
-
-  private boolean analysisHasSize(EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
-  {
-    return analysisTypes.contains(SegmentMetadataQuery.AnalysisType.SIZE);
-  }
-
-  private boolean analysisHasCardinality(EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes)
-  {
-    return analysisTypes.contains(SegmentMetadataQuery.AnalysisType.CARDINALITY);
-  }
 }

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

@@ -148,7 +148,7 @@ public class SegmentMetadataQueryQueryToolChest extends QueryToolChest<SegmentAn
             }
 
             List<Interval> newIntervals = null;
-            if (query.hasInterval()) {
+            if (query.analyzingInterval()) {
               //List returned by arg1.getIntervals() is immutable, so a new list needs to
               //be created.
               newIntervals = new ArrayList<>(arg1.getIntervals());

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

@@ -43,9 +43,7 @@ import io.druid.query.metadata.metadata.ColumnAnalysis;
 import io.druid.query.metadata.metadata.ColumnIncluderator;
 import io.druid.query.metadata.metadata.SegmentAnalysis;
 import io.druid.query.metadata.metadata.SegmentMetadataQuery;
-import io.druid.segment.QueryableIndex;
 import io.druid.segment.Segment;
-import io.druid.segment.StorageAdapter;
 import org.joda.time.Interval;
 
 import java.util.ArrayList;
@@ -60,7 +58,6 @@ import java.util.concurrent.TimeoutException;
 
 public class SegmentMetadataQueryRunnerFactory implements QueryRunnerFactory<SegmentAnalysis, SegmentMetadataQuery>
 {
-  private static final SegmentAnalyzer analyzer = new SegmentAnalyzer();
   private static final Logger log = new Logger(SegmentMetadataQueryRunnerFactory.class);
 
 
@@ -86,23 +83,12 @@ public class SegmentMetadataQueryRunnerFactory implements QueryRunnerFactory<Seg
       public Sequence<SegmentAnalysis> run(Query<SegmentAnalysis> inQ, Map<String, Object> responseContext)
       {
         SegmentMetadataQuery query = (SegmentMetadataQuery) inQ;
-
+        final SegmentAnalyzer analyzer = new SegmentAnalyzer(query.getAnalysisTypes());
-        final QueryableIndex index = segment.asQueryableIndex();
+        final Map<String, ColumnAnalysis> analyzedColumns = analyzer.analyze(segment);
-
+        final int numRows = analyzer.numRows(segment);
-        final Map<String, ColumnAnalysis> analyzedColumns;
-        final int numRows;
         long totalSize = 0;
-        if (index == null) {
-          // IncrementalIndexSegments (used by in-memory hydrants in the realtime service) do not have a QueryableIndex
-          StorageAdapter segmentAdapter = segment.asStorageAdapter();
-          analyzedColumns = analyzer.analyze(segmentAdapter, query.getAnalysisTypes());
-          numRows = segmentAdapter.getNumRows();
-        } else {
-          analyzedColumns = analyzer.analyze(index, query.getAnalysisTypes());
-          numRows = index.getNumRows();
-        }
 
-        if (query.hasSize()) {
+        if (analyzer.analyzingSize()) {
           // Initialize with the size of the whitespace, 1 byte per
           totalSize = analyzedColumns.size() * numRows;
         }
@@ -120,7 +106,7 @@ public class SegmentMetadataQueryRunnerFactory implements QueryRunnerFactory<Seg
             columns.put(columnName, column);
           }
         }
-        List<Interval> retIntervals = query.hasInterval() ? Arrays.asList(segment.getDataInterval()) : null;
+        List<Interval> retIntervals = query.analyzingInterval() ? Arrays.asList(segment.getDataInterval()) : null;
 
         return Sequences.simple(
             Arrays.asList(

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

@@ -22,6 +22,8 @@ package io.druid.query.metadata.metadata;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import java.util.Objects;
+
 /**
  */
 public class ColumnAnalysis
@@ -30,10 +32,11 @@ public class ColumnAnalysis
 
   public static ColumnAnalysis error(String reason)
   {
-    return new ColumnAnalysis("STRING", -1, null, ERROR_PREFIX + reason);
+    return new ColumnAnalysis("STRING", false, -1, null, ERROR_PREFIX + reason);
   }
 
   private final String type;
+  private final boolean hasMultipleValues;
   private final long size;
   private final Integer cardinality;
   private final String errorMessage;
@@ -41,12 +44,14 @@ public class ColumnAnalysis
   @JsonCreator
   public ColumnAnalysis(
       @JsonProperty("type") String type,
+      @JsonProperty("hasMultipleValues") boolean hasMultipleValues,
       @JsonProperty("size") long size,
       @JsonProperty("cardinality") Integer cardinality,
       @JsonProperty("errorMessage") String errorMessage
   )
   {
     this.type = type;
+    this.hasMultipleValues = hasMultipleValues;
     this.size = size;
     this.cardinality = cardinality;
     this.errorMessage = errorMessage;
@@ -58,6 +63,12 @@ public class ColumnAnalysis
     return type;
   }
 
+  @JsonProperty
+  public boolean isHasMultipleValues()
+  {
+    return hasMultipleValues;
+  }
+
   @JsonProperty
   public long getSize()
   {
@@ -96,14 +107,19 @@ public class ColumnAnalysis
     if (cardinality == null) {
 
       cardinality = rhsCardinality;
-    }
+    } else {
-    else {
       if (rhsCardinality != null) {
         cardinality = Math.max(cardinality, rhsCardinality);
       }
     }
 
-    return new ColumnAnalysis(type, size + rhs.getSize(), cardinality, null);
+    return new ColumnAnalysis(
+        type,
+        hasMultipleValues || rhs.isHasMultipleValues(),
+        size + rhs.getSize(),
+        cardinality,
+        null
+    );
   }
 
   @Override
@@ -111,6 +127,7 @@ public class ColumnAnalysis
   {
     return "ColumnAnalysis{" +
            "type='" + type + '\'' +
+           ", hasMultipleValues=" + hasMultipleValues +
            ", size=" + size +
            ", cardinality=" + cardinality +
            ", errorMessage='" + errorMessage + '\'' +
@@ -126,29 +143,17 @@ public class ColumnAnalysis
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-
     ColumnAnalysis that = (ColumnAnalysis) o;
-
+    return hasMultipleValues == that.hasMultipleValues &&
-    if (size != that.size) {
+           size == that.size &&
-      return false;
+           Objects.equals(type, that.type) &&
-    }
+           Objects.equals(cardinality, that.cardinality) &&
-    if (type != null ? !type.equals(that.type) : that.type != null) {
+           Objects.equals(errorMessage, that.errorMessage);
-      return false;
-    }
-    if (cardinality != null ? !cardinality.equals(that.cardinality) : that.cardinality != null) {
-      return false;
-    }
-    return !(errorMessage != null ? !errorMessage.equals(that.errorMessage) : that.errorMessage != null);
-
   }
 
   @Override
   public int hashCode()
   {
-    int result = type != null ? type.hashCode() : 0;
+    return Objects.hash(type, hasMultipleValues, size, cardinality, errorMessage);
-    result = 31 * result + (int) (size ^ (size >>> 32));
-    result = 31 * result + (cardinality != null ? cardinality.hashCode() : 0);
-    result = 31 * result + (errorMessage != null ? errorMessage.hashCode() : 0);
-    return result;
   }
 }

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

@@ -98,6 +98,7 @@ public class SegmentAnalysis implements Comparable<SegmentAnalysis>
     return "SegmentAnalysis{" +
            "id='" + id + '\'' +
            ", interval=" + interval +
+           ", columns=" + columns +
            ", size=" + size +
            ", numRows=" + numRows +
            '}';

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

@@ -151,22 +151,12 @@ public class SegmentMetadataQuery extends BaseQuery<SegmentAnalysis>
   }
 
   @JsonProperty
-  public EnumSet getAnalysisTypes()
+  public EnumSet<AnalysisType> getAnalysisTypes()
   {
     return analysisTypes;
   }
 
-  public boolean hasCardinality()
+  public boolean analyzingInterval()
-  {
-    return analysisTypes.contains(AnalysisType.CARDINALITY);
-  }
-
-  public boolean hasSize()
-  {
-    return analysisTypes.contains(AnalysisType.SIZE);
-  }
-
-  public boolean hasInterval()
   {
     return analysisTypes.contains(AnalysisType.INTERVAL);
   }

processing/src/main/java/io/druid/segment/QueryableIndexStorageAdapter.java

@@ -152,6 +152,14 @@ public class QueryableIndexStorageAdapter implements StorageAdapter
     return index.getColumn(column).getCapabilities();
   }
 
+  @Override
+  public String getColumnTypeName(String columnName)
+  {
+    final Column column = index.getColumn(columnName);
+    final ComplexColumn complexColumn = column.getComplexColumn();
+    return complexColumn != null ? complexColumn.getTypeName() : column.getCapabilities().getType().toString();
+  }
+
   @Override
   public DateTime getMaxIngestedEventTime()
   {

processing/src/main/java/io/druid/segment/StorageAdapter.java

@@ -46,6 +46,13 @@ public interface StorageAdapter extends CursorFactory
   public DateTime getMaxTime();
   public Capabilities getCapabilities();
   public ColumnCapabilities getColumnCapabilities(String column);
+
+  /**
+   * Like {@link ColumnCapabilities#getType()}, but may return a more descriptive string for complex columns.
+   * @param column column name
+   * @return type name
+   */
+  public String getColumnTypeName(String column);
   public int getNumRows();
   public DateTime getMaxIngestedEventTime();
 }

processing/src/main/java/io/druid/segment/incremental/IncrementalIndex.java

@@ -569,7 +569,8 @@ public abstract class IncrementalIndex<AggregatorType> implements Iterable<Row>,
 
   public String getMetricType(String metric)
   {
-    return metricDescs.get(metric).getType();
+    final MetricDesc metricDesc = metricDescs.get(metric);
+    return metricDesc != null ? metricDesc.getType() : null;
   }
 
   public Interval getInterval()

processing/src/main/java/io/druid/segment/incremental/IncrementalIndexStorageAdapter.java

@@ -147,6 +147,13 @@ public class IncrementalIndexStorageAdapter implements StorageAdapter
     return index.getCapabilities(column);
   }
 
+  @Override
+  public String getColumnTypeName(String column)
+  {
+    final String metricType = index.getMetricType(column);
+    return metricType != null ? metricType : getColumnCapabilities(column).getType().toString();
+  }
+
   @Override
   public DateTime getMaxIngestedEventTime()
   {

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

@@ -310,15 +310,13 @@ public class QueryRunnerTestHelper
   )
       throws IOException
   {
-    final IncrementalIndex rtIndex = TestIndex.getIncrementalTestIndex(false);
+    final IncrementalIndex rtIndex = TestIndex.getIncrementalTestIndex();
     final QueryableIndex mMappedTestIndex = TestIndex.getMMappedTestIndex();
     final QueryableIndex mergedRealtimeIndex = TestIndex.mergedRealtimeIndex();
-    final IncrementalIndex rtIndexOffheap = TestIndex.getIncrementalTestIndex(true);
     return ImmutableList.of(
         makeQueryRunner(factory, new IncrementalIndexSegment(rtIndex, segmentId)),
         makeQueryRunner(factory, new QueryableIndexSegment(segmentId, mMappedTestIndex)),
-        makeQueryRunner(factory, new QueryableIndexSegment(segmentId, mergedRealtimeIndex)),
+        makeQueryRunner(factory, new QueryableIndexSegment(segmentId, mergedRealtimeIndex))
-        makeQueryRunner(factory, new IncrementalIndexSegment(rtIndexOffheap, segmentId))
     );
   }
 
@@ -329,10 +327,9 @@ public class QueryRunnerTestHelper
   )
       throws IOException
   {
-    final IncrementalIndex rtIndex = TestIndex.getIncrementalTestIndex(false);
+    final IncrementalIndex rtIndex = TestIndex.getIncrementalTestIndex();
     final QueryableIndex mMappedTestIndex = TestIndex.getMMappedTestIndex();
     final QueryableIndex mergedRealtimeIndex = TestIndex.mergedRealtimeIndex();
-    final IncrementalIndex rtIndexOffheap = TestIndex.getIncrementalTestIndex(true);
 
     return Arrays.asList(
         makeUnionQueryRunner(factory, new IncrementalIndexSegment(rtIndex, segmentId)),
@@ -340,8 +337,7 @@ public class QueryRunnerTestHelper
         makeUnionQueryRunner(
             factory,
             new QueryableIndexSegment(segmentId, mergedRealtimeIndex)
-        ),
+        )
-        makeUnionQueryRunner(factory, new IncrementalIndexSegment(rtIndexOffheap, segmentId))
     );
   }
   /**

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

@@ -59,7 +59,7 @@ public class SegmentAnalyzerTest
   private void testIncrementalWorksHelper(EnumSet<SegmentMetadataQuery.AnalysisType> analyses) throws Exception
   {
     final List<SegmentAnalysis> results = getSegmentAnalysises(
-        new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(false), null),
+        new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(), null),
         analyses
     );
 

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

@@ -67,6 +67,7 @@ public class SegmentMetadataQueryQueryToolChestTest
             "placement",
             new ColumnAnalysis(
                 ValueType.STRING.toString(),
+                true,
                 10881,
                 1,
                 null

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

@@ -43,6 +43,7 @@ import io.druid.query.metadata.metadata.ColumnAnalysis;
 import io.druid.query.metadata.metadata.ListColumnIncluderator;
 import io.druid.query.metadata.metadata.SegmentAnalysis;
 import io.druid.query.metadata.metadata.SegmentMetadataQuery;
+import io.druid.segment.IncrementalIndexSegment;
 import io.druid.segment.QueryableIndexSegment;
 import io.druid.segment.TestHelper;
 import io.druid.segment.TestIndex;
@@ -51,27 +52,27 @@ import io.druid.timeline.LogicalSegment;
 import org.joda.time.Interval;
 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.EnumSet;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
+@RunWith(Parameterized.class)
 public class SegmentMetadataQueryTest
 {
-  private final SegmentMetadataQueryRunnerFactory factory = new SegmentMetadataQueryRunnerFactory(
+  private static final SegmentMetadataQueryRunnerFactory FACTORY = new SegmentMetadataQueryRunnerFactory(
       new SegmentMetadataQueryQueryToolChest(new SegmentMetadataQueryConfig()),
       QueryRunnerTestHelper.NOOP_QUERYWATCHER
   );
+  private static final ObjectMapper MAPPER = new DefaultObjectMapper();
 
   @SuppressWarnings("unchecked")
-  private final QueryRunner runner = makeQueryRunner(factory);
+  public static QueryRunner makeMMappedQueryRunner(
-
-  private final ObjectMapper mapper = new DefaultObjectMapper();
-
-  @SuppressWarnings("unchecked")
-  public static QueryRunner makeQueryRunner(
       QueryRunnerFactory factory
   )
   {
@@ -81,15 +82,39 @@ public class SegmentMetadataQueryTest
     );
   }
 
+  @SuppressWarnings("unchecked")
+  public static QueryRunner makeIncrementalIndexQueryRunner(
+      QueryRunnerFactory factory
+  )
+  {
+    return QueryRunnerTestHelper.makeQueryRunner(
+        factory,
+        new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(), QueryRunnerTestHelper.segmentId)
+    );
+  }
+
+  private final QueryRunner runner;
+  private final boolean usingMmappedSegment;
   private final SegmentMetadataQuery testQuery;
   private final SegmentAnalysis expectedSegmentAnalysis;
 
-  public SegmentMetadataQueryTest()
+  @Parameterized.Parameters(name = "runner = {1}")
+  public static Collection<Object[]> constructorFeeder()
   {
+    return ImmutableList.of(
+        new Object[]{makeMMappedQueryRunner(FACTORY), "mmap", true},
+        new Object[]{makeIncrementalIndexQueryRunner(FACTORY), "incremental", false}
+    );
+  }
+
+  public SegmentMetadataQueryTest(QueryRunner runner, String runnerName, boolean usingMmappedSegment)
+  {
+    this.runner = runner;
+    this.usingMmappedSegment = usingMmappedSegment;
     testQuery = Druids.newSegmentMetadataQueryBuilder()
                       .dataSource("testing")
                       .intervals("2013/2014")
-                      .toInclude(new ListColumnIncluderator(Arrays.asList("placement")))
+                      .toInclude(new ListColumnIncluderator(Arrays.asList("__time", "index", "placement")))
                       .analysisTypes(null)
                       .merge(true)
                       .build();
@@ -100,14 +125,31 @@ public class SegmentMetadataQueryTest
             new Interval("2011-01-12T00:00:00.000Z/2011-04-15T00:00:00.001Z")
         ),
         ImmutableMap.of(
+            "__time",
+            new ColumnAnalysis(
+                ValueType.LONG.toString(),
+                false,
+                12090,
+                null,
+                null
+            ),
             "placement",
             new ColumnAnalysis(
                 ValueType.STRING.toString(),
-                10881,
+                false,
+                usingMmappedSegment ? 10881 : 0,
                 1,
                 null
+            ),
+            "index",
+            new ColumnAnalysis(
+                ValueType.FLOAT.toString(),
+                false,
+                9672,
+                null,
+                null
             )
-        ), 71982,
+        ), usingMmappedSegment ? 71982 : 32643,
         1209
     );
   }
@@ -124,6 +166,124 @@ public class SegmentMetadataQueryTest
     Assert.assertEquals(Arrays.asList(expectedSegmentAnalysis), results);
   }
 
+  @Test
+  public void testSegmentMetadataQueryWithHasMultipleValuesMerge()
+  {
+    SegmentAnalysis mergedSegmentAnalysis = new SegmentAnalysis(
+        "merged",
+        null,
+        ImmutableMap.of(
+            "placement",
+            new ColumnAnalysis(
+                ValueType.STRING.toString(),
+                false,
+                0,
+                1,
+                null
+            ),
+            "placementish",
+            new ColumnAnalysis(
+                ValueType.STRING.toString(),
+                true,
+                0,
+                9,
+                null
+            )
+        ),
+        0,
+        expectedSegmentAnalysis.getNumRows() * 2
+    );
+
+    QueryToolChest toolChest = FACTORY.getToolchest();
+
+    QueryRunner singleSegmentQueryRunner = toolChest.preMergeQueryDecoration(runner);
+    ExecutorService exec = Executors.newCachedThreadPool();
+    QueryRunner myRunner = new FinalizeResultsQueryRunner<>(
+        toolChest.mergeResults(
+            FACTORY.mergeRunners(
+                MoreExecutors.sameThreadExecutor(),
+                Lists.<QueryRunner<SegmentAnalysis>>newArrayList(singleSegmentQueryRunner, singleSegmentQueryRunner)
+            )
+        ),
+        toolChest
+    );
+
+    TestHelper.assertExpectedObjects(
+        ImmutableList.of(mergedSegmentAnalysis),
+        myRunner.run(
+            Druids.newSegmentMetadataQueryBuilder()
+                  .dataSource("testing")
+                  .intervals("2013/2014")
+                  .toInclude(new ListColumnIncluderator(Arrays.asList("placement", "placementish")))
+                  .analysisTypes(SegmentMetadataQuery.AnalysisType.CARDINALITY)
+                  .merge(true)
+                  .build(),
+            Maps.newHashMap()
+        ),
+        "failed SegmentMetadata merging query"
+    );
+    exec.shutdownNow();
+  }
+
+  @Test
+  public void testSegmentMetadataQueryWithComplexColumnMerge()
+  {
+    SegmentAnalysis mergedSegmentAnalysis = new SegmentAnalysis(
+        "merged",
+        null,
+        ImmutableMap.of(
+            "placement",
+            new ColumnAnalysis(
+                ValueType.STRING.toString(),
+                false,
+                0,
+                1,
+                null
+            ),
+            "quality_uniques",
+            new ColumnAnalysis(
+                "hyperUnique",
+                false,
+                0,
+                null,
+                null
+            )
+        ),
+        0,
+        expectedSegmentAnalysis.getNumRows() * 2
+    );
+
+    QueryToolChest toolChest = FACTORY.getToolchest();
+
+    QueryRunner singleSegmentQueryRunner = toolChest.preMergeQueryDecoration(runner);
+    ExecutorService exec = Executors.newCachedThreadPool();
+    QueryRunner myRunner = new FinalizeResultsQueryRunner<>(
+        toolChest.mergeResults(
+            FACTORY.mergeRunners(
+                MoreExecutors.sameThreadExecutor(),
+                Lists.<QueryRunner<SegmentAnalysis>>newArrayList(singleSegmentQueryRunner, singleSegmentQueryRunner)
+            )
+        ),
+        toolChest
+    );
+
+    TestHelper.assertExpectedObjects(
+        ImmutableList.of(mergedSegmentAnalysis),
+        myRunner.run(
+            Druids.newSegmentMetadataQueryBuilder()
+                  .dataSource("testing")
+                  .intervals("2013/2014")
+                  .toInclude(new ListColumnIncluderator(Arrays.asList("placement", "quality_uniques")))
+                  .analysisTypes(SegmentMetadataQuery.AnalysisType.CARDINALITY)
+                  .merge(true)
+                  .build(),
+            Maps.newHashMap()
+        ),
+        "failed SegmentMetadata merging query"
+    );
+    exec.shutdownNow();
+  }
+
   @Test
   public void testSegmentMetadataQueryWithDefaultAnalysisMerge()
   {
@@ -131,25 +291,42 @@ public class SegmentMetadataQueryTest
         "merged",
         ImmutableList.of(expectedSegmentAnalysis.getIntervals().get(0)),
         ImmutableMap.of(
+            "__time",
+            new ColumnAnalysis(
+                ValueType.LONG.toString(),
+                false,
+                12090 * 2,
+                null,
+                null
+            ),
             "placement",
             new ColumnAnalysis(
                 ValueType.STRING.toString(),
-                21762,
+                false,
+                usingMmappedSegment ? 21762 : 0,
                 1,
                 null
+            ),
+            "index",
+            new ColumnAnalysis(
+                ValueType.FLOAT.toString(),
+                false,
+                9672 * 2,
+                null,
+                null
             )
         ),
         expectedSegmentAnalysis.getSize() * 2,
         expectedSegmentAnalysis.getNumRows() * 2
     );
 
-    QueryToolChest toolChest = factory.getToolchest();
+    QueryToolChest toolChest = FACTORY.getToolchest();
 
     QueryRunner singleSegmentQueryRunner = toolChest.preMergeQueryDecoration(runner);
     ExecutorService exec = Executors.newCachedThreadPool();
     QueryRunner myRunner = new FinalizeResultsQueryRunner<>(
         toolChest.mergeResults(
-            factory.mergeRunners(
+            FACTORY.mergeRunners(
                 MoreExecutors.sameThreadExecutor(),
                 Lists.<QueryRunner<SegmentAnalysis>>newArrayList(singleSegmentQueryRunner, singleSegmentQueryRunner)
             )
@@ -178,6 +355,7 @@ public class SegmentMetadataQueryTest
             "placement",
             new ColumnAnalysis(
                 ValueType.STRING.toString(),
+                false,
                 0,
                 0,
                 null
@@ -187,13 +365,13 @@ public class SegmentMetadataQueryTest
         expectedSegmentAnalysis.getNumRows() * 2
     );
 
-    QueryToolChest toolChest = factory.getToolchest();
+    QueryToolChest toolChest = FACTORY.getToolchest();
 
     QueryRunner singleSegmentQueryRunner = toolChest.preMergeQueryDecoration(runner);
     ExecutorService exec = Executors.newCachedThreadPool();
     QueryRunner myRunner = new FinalizeResultsQueryRunner<>(
         toolChest.mergeResults(
-            factory.mergeRunners(
+            FACTORY.mergeRunners(
                 MoreExecutors.sameThreadExecutor(),
                 Lists.<QueryRunner<SegmentAnalysis>>newArrayList(singleSegmentQueryRunner, singleSegmentQueryRunner)
             )
@@ -230,13 +408,13 @@ public class SegmentMetadataQueryTest
         )
     );
 
-    QueryToolChest toolChest = factory.getToolchest();
+    QueryToolChest toolChest = FACTORY.getToolchest();
 
     QueryRunner singleSegmentQueryRunner = toolChest.preMergeQueryDecoration(runner);
     ExecutorService exec = Executors.newCachedThreadPool();
     QueryRunner myRunner = new FinalizeResultsQueryRunner<>(
         toolChest.mergeResults(
-            factory.mergeRunners(
+            FACTORY.mergeRunners(
                 MoreExecutors.sameThreadExecutor(),
                 //Note: It is essential to have atleast 2 query runners merged to reproduce the regression bug described in
                 //https://github.com/druid-io/druid/pull/1172
@@ -273,14 +451,14 @@ public class SegmentMetadataQueryTest
         SegmentMetadataQuery.AnalysisType.SIZE
     );
 
-    Query query = mapper.readValue(queryStr, Query.class);
+    Query query = MAPPER.readValue(queryStr, Query.class);
     Assert.assertTrue(query instanceof SegmentMetadataQuery);
     Assert.assertEquals("test_ds", Iterables.getOnlyElement(query.getDataSource().getNames()));
     Assert.assertEquals(new Interval("2013-12-04T00:00:00.000Z/2013-12-05T00:00:00.000Z"), query.getIntervals().get(0));
     Assert.assertEquals(expectedAnalysisTypes, ((SegmentMetadataQuery) query).getAnalysisTypes());
 
     // test serialize and deserialize
-    Assert.assertEquals(query, mapper.readValue(mapper.writeValueAsString(query), Query.class));
+    Assert.assertEquals(query, MAPPER.readValue(MAPPER.writeValueAsString(query), Query.class));
   }
 
   @Test
@@ -290,14 +468,14 @@ public class SegmentMetadataQueryTest
                       + "  \"queryType\":\"segmentMetadata\",\n"
                       + "  \"dataSource\":\"test_ds\"\n"
                       + "}";
-    Query query = mapper.readValue(queryStr, Query.class);
+    Query query = MAPPER.readValue(queryStr, Query.class);
     Assert.assertTrue(query instanceof SegmentMetadataQuery);
     Assert.assertEquals("test_ds", Iterables.getOnlyElement(query.getDataSource().getNames()));
     Assert.assertEquals(new Interval(JodaUtils.MIN_INSTANT, JodaUtils.MAX_INSTANT), query.getIntervals().get(0));
     Assert.assertTrue(((SegmentMetadataQuery) query).isUsingDefaultInterval());
 
     // test serialize and deserialize
-    Assert.assertEquals(query, mapper.readValue(mapper.writeValueAsString(query), Query.class));
+    Assert.assertEquals(query, MAPPER.readValue(MAPPER.writeValueAsString(query), Query.class));
   }
 
   @Test

processing/src/test/java/io/druid/query/search/SearchQueryRunnerWithCaseTest.java

@@ -83,8 +83,8 @@ public class SearchQueryRunnerWithCaseTest
         "2011-01-13T00:00:00.000Z\tspot\tautomotive\tpreferred\ta\u0001preferred\t94.874713"
     );
 
-    IncrementalIndex index1 = TestIndex.makeRealtimeIndex(input, true);
+    IncrementalIndex index1 = TestIndex.makeRealtimeIndex(input);
-    IncrementalIndex index2 = TestIndex.makeRealtimeIndex(input, false);
+    IncrementalIndex index2 = TestIndex.makeRealtimeIndex(input);
 
     QueryableIndex index3 = TestIndex.persistRealtimeAndLoadMMapped(index1);
     QueryableIndex index4 = TestIndex.persistRealtimeAndLoadMMapped(index2);

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

@@ -121,7 +121,7 @@ public class TopNQueryQueryToolChestTest
     );
     QueryRunner<Result<TopNResultValue>> runner = QueryRunnerTestHelper.makeQueryRunner(
         factory,
-        new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(false), segmentId)
+        new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(), segmentId)
     );
 
     Map<String, Object> context = Maps.newHashMap();

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

@@ -106,7 +106,7 @@ public class TopNQueryRunnerBenchmark extends AbstractBenchmark
         TestCases.rtIndex,
         QueryRunnerTestHelper.makeQueryRunner(
             factory,
-            new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(false), segmentId)
+            new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(), segmentId)
         )
     );
     testCaseMap.put(
@@ -123,13 +123,6 @@ public class TopNQueryRunnerBenchmark extends AbstractBenchmark
             new QueryableIndexSegment(segmentId, TestIndex.mergedRealtimeIndex())
         )
     );
-    testCaseMap.put(
-        TestCases.rtIndexOffheap,
-        QueryRunnerTestHelper.makeQueryRunner(
-            factory,
-            new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(true), segmentId)
-        )
-    );
     //Thread.sleep(10000);
   }
 

processing/src/test/java/io/druid/segment/TestIndex.java

@@ -93,7 +93,7 @@ public class TestIndex
   private static QueryableIndex mmappedIndex = null;
   private static QueryableIndex mergedRealtime = null;
 
-  public static IncrementalIndex getIncrementalTestIndex(boolean useOffheap)
+  public static IncrementalIndex getIncrementalTestIndex()
   {
     synchronized (log) {
       if (realtimeIndex != null) {
@@ -101,7 +101,7 @@ public class TestIndex
       }
     }
 
-    return realtimeIndex = makeRealtimeIndex("druid.sample.tsv", useOffheap);
+    return realtimeIndex = makeRealtimeIndex("druid.sample.tsv");
   }
 
   public static QueryableIndex getMMappedTestIndex()
@@ -112,7 +112,7 @@ public class TestIndex
       }
     }
 
-    IncrementalIndex incrementalIndex = getIncrementalTestIndex(false);
+    IncrementalIndex incrementalIndex = getIncrementalTestIndex();
     mmappedIndex = persistRealtimeAndLoadMMapped(incrementalIndex);
 
     return mmappedIndex;
@@ -126,8 +126,8 @@ public class TestIndex
       }
 
       try {
-        IncrementalIndex top = makeRealtimeIndex("druid.sample.tsv.top", false);
+        IncrementalIndex top = makeRealtimeIndex("druid.sample.tsv.top");
-        IncrementalIndex bottom = makeRealtimeIndex("druid.sample.tsv.bottom", false);
+        IncrementalIndex bottom = makeRealtimeIndex("druid.sample.tsv.bottom");
 
         File tmpFile = File.createTempFile("yay", "who");
         tmpFile.delete();
@@ -163,7 +163,7 @@ public class TestIndex
     }
   }
 
-  private static IncrementalIndex makeRealtimeIndex(final String resourceFilename, final boolean useOffheap)
+  private static IncrementalIndex makeRealtimeIndex(final String resourceFilename)
   {
     final URL resource = TestIndex.class.getClassLoader().getResource(resourceFilename);
     if (resource == null) {
@@ -171,10 +171,10 @@ public class TestIndex
     }
     log.info("Realtime loading index file[%s]", resource);
     CharSource stream = Resources.asByteSource(resource).asCharSource(Charsets.UTF_8);
-    return makeRealtimeIndex(stream, useOffheap);
+    return makeRealtimeIndex(stream);
   }
 
-  public static IncrementalIndex makeRealtimeIndex(final CharSource source, final boolean useOffheap)
+  public static IncrementalIndex makeRealtimeIndex(final CharSource source)
   {
     final IncrementalIndexSchema schema = new IncrementalIndexSchema.Builder()
         .withMinTimestamp(new DateTime("2011-01-12T00:00:00.000Z").getMillis())