More efficient SegmentMetadataQuery

common/src/main/java/io/druid/common/guava/CombiningSequence.java

@@ -19,6 +19,7 @@
 
 package io.druid.common.guava;
 
+import com.google.common.base.Function;
 import com.google.common.collect.Ordering;
 import com.metamx.common.guava.Accumulator;
 import com.metamx.common.guava.Sequence;
@@ -37,25 +38,29 @@ public class CombiningSequence<T> implements Sequence<T>
   public static <T> CombiningSequence<T> create(
       Sequence<T> baseSequence,
       Ordering<T> ordering,
-      BinaryFn<T, T, T> mergeFn
+      BinaryFn<T, T, T> mergeFn,
+      Function transformFn
   )
   {
-    return new CombiningSequence<T>(baseSequence, ordering, mergeFn);
+    return new CombiningSequence<T>(baseSequence, ordering, mergeFn, transformFn);
   }
 
   private final Sequence<T> baseSequence;
   private final Ordering<T> ordering;
   private final BinaryFn<T, T, T> mergeFn;
+  private final Function transformFn;
 
   public CombiningSequence(
       Sequence<T> baseSequence,
       Ordering<T> ordering,
-      BinaryFn<T, T, T> mergeFn
+      BinaryFn<T, T, T> mergeFn,
+      Function transformFn
   )
   {
     this.baseSequence = baseSequence;
     this.ordering = ordering;
     this.mergeFn = mergeFn;
+    this.transformFn = transformFn;
   }
 
   @Override
@@ -117,6 +122,9 @@ public class CombiningSequence<T> implements Sequence<T>
       @Override
       public OutType get()
       {
+        if (transformFn != null) {
+          return (OutType) transformFn.apply(retVal);
+        }
         return retVal;
       }
 

common/src/test/java/io/druid/common/guava/CombiningSequenceTest.java

@@ -214,7 +214,8 @@ public class CombiningSequenceTest
 
             return Pair.of(lhs.lhs, lhs.rhs + rhs.rhs);
           }
-        }
+        },
+        null
     );
 
     List<Pair<Integer, Integer>> merged = Sequences.toList(seq, Lists.<Pair<Integer, Integer>>newArrayList());

docs/content/querying/segmentmetadataquery.md

@@ -30,7 +30,7 @@ There are several main parts to a segment metadata query:
 |toInclude|A JSON Object representing what columns should be included in the result. Defaults to "all".|no|
 |merge|Merge all individual segment metadata results into a single result|no|
 |context|See [Context](../querying/query-context.html)|no|
-|analysisTypes|A list of Strings specifying what column properties (e.g. cardinality, size) should be calculated and returned in the result. Defaults to ["cardinality", "size"]. See section [analysisTypes](#analysistypes) for more details.|no|
+|analysisTypes|A list of Strings specifying what column properties (e.g. cardinality, size) should be calculated and returned in the result. Defaults to ["cardinality", "size", "interval"]. See section [analysisTypes](#analysistypes) for more details.|no|
 
 The format of the result is:
 
@@ -96,7 +96,7 @@ This is a list of properties that determines the amount of information returned
 
 By default, all analysis types will be used. If a property is not needed, omitting it from this list will result in a more efficient query.
 
-There are 2 types of column analyses:
+There are 3 types of column analyses:
 
 #### cardinality
 
@@ -107,3 +107,7 @@ There are 2 types of column analyses:
 * Estimated byte size for the segment columns if they were stored in a flat format
 
 * Estimated total segment byte size in if it was stored in a flat format
+
+#### interval
+
+* If present, the SegmentMetadataQuery will return the list of intervals associated with the queried segments.

processing/src/main/java/io/druid/query/ResultMergeQueryRunner.java

@@ -40,7 +40,7 @@ public abstract class ResultMergeQueryRunner<T> extends BySegmentSkippingQueryRu
   @Override
   public Sequence<T> doRun(QueryRunner<T> baseRunner, Query<T> query, Map<String, Object> context)
   {
-    return CombiningSequence.create(baseRunner.run(query, context), makeOrdering(query), createMergeFn(query));
+    return CombiningSequence.create(baseRunner.run(query, context), makeOrdering(query), createMergeFn(query), null);
   }
 
   protected abstract Ordering<T> makeOrdering(Query<T> query);

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

@@ -281,4 +281,8 @@ public class SegmentAnalyzer
     return analysisTypes.contains(SegmentMetadataQuery.AnalysisType.CARDINALITY);
   }
 
+  private boolean analysisHasInterva(EnumSet<SegmentMetadataQuery.AnalysisType> analysisTypes) {
+    return analysisTypes.contains(SegmentMetadataQuery.AnalysisType.INTERVAL);
+  }
+
 }

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

@@ -34,7 +34,9 @@ import com.metamx.common.guava.Sequence;
 import com.metamx.common.guava.nary.BinaryFn;
 import com.metamx.emitter.service.ServiceMetricEvent;
 import io.druid.collections.OrderedMergeSequence;
+import io.druid.common.guava.CombiningSequence;
 import io.druid.common.utils.JodaUtils;
+import io.druid.data.input.Row;
 import io.druid.query.CacheStrategy;
 import io.druid.query.DruidMetrics;
 import io.druid.query.Query;
@@ -77,6 +79,36 @@ public class SegmentMetadataQueryQueryToolChest extends QueryToolChest<SegmentAn
   {
     return new ResultMergeQueryRunner<SegmentAnalysis>(runner)
     {
+      private Function<SegmentAnalysis, SegmentAnalysis> transformFn = new Function<SegmentAnalysis, SegmentAnalysis>()
+      {
+        @Override
+        public SegmentAnalysis apply(SegmentAnalysis analysis)
+        {
+          return new SegmentAnalysis(
+              analysis.getId(),
+              JodaUtils.condenseIntervals(analysis.getIntervals()),
+              analysis.getColumns(),
+              analysis.getSize(),
+              analysis.getNumRows()
+          );
+        }
+      };
+
+      @Override
+      public Sequence<SegmentAnalysis> doRun(
+          QueryRunner<SegmentAnalysis> baseRunner,
+          Query<SegmentAnalysis> query,
+          Map<String, Object> context
+      )
+      {
+        return CombiningSequence.create(
+            baseRunner.run(query, context),
+            makeOrdering(query),
+            createMergeFn(query),
+            transformFn
+        );
+      }
+
       @Override
       protected Ordering<SegmentAnalysis> makeOrdering(Query<SegmentAnalysis> query)
       {
@@ -115,9 +147,11 @@ public class SegmentMetadataQueryQueryToolChest extends QueryToolChest<SegmentAn
               return arg1;
             }
 
-            List<Interval> newIntervals = JodaUtils.condenseIntervals(
+            List<Interval> newIntervals = null;
-                Iterables.concat(arg1.getIntervals(), arg2.getIntervals())
+            if (query.hasInterval()) {
-            );
+              newIntervals = arg1.getIntervals();
+              newIntervals.addAll(arg2.getIntervals());
+            }
 
             final Map<String, ColumnAnalysis> leftColumns = arg1.getColumns();
             final Map<String, ColumnAnalysis> rightColumns = arg2.getColumns();

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

@@ -45,9 +45,11 @@ 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;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
@@ -117,12 +119,13 @@ public class SegmentMetadataQueryRunnerFactory implements QueryRunnerFactory<Seg
             columns.put(columnName, column);
           }
         }
+        List<Interval> retIntervals = query.hasInterval() ? Arrays.asList(segment.getDataInterval()) : null;
 
         return Sequences.simple(
             Arrays.asList(
                 new SegmentAnalysis(
                     segment.getIdentifier(),
-                    Arrays.asList(segment.getDataInterval()),
+                    retIntervals,
                     columns,
                     totalSize,
                     numRows

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

@@ -50,7 +50,8 @@ public class SegmentMetadataQuery extends BaseQuery<SegmentAnalysis>
   public enum AnalysisType
   {
     CARDINALITY,
-    SIZE;
+    SIZE,
+    INTERVAL;
 
     @JsonValue
     @Override
@@ -77,7 +78,8 @@ public class SegmentMetadataQuery extends BaseQuery<SegmentAnalysis>
 
   public static final EnumSet<AnalysisType> DEFAULT_ANALYSIS_TYPES = EnumSet.of(
       AnalysisType.CARDINALITY,
-      AnalysisType.SIZE
+      AnalysisType.SIZE,
+      AnalysisType.INTERVAL
   );
 
   private final ColumnIncluderator toInclude;
@@ -163,6 +165,11 @@ public class SegmentMetadataQuery extends BaseQuery<SegmentAnalysis>
     return analysisTypes.contains(AnalysisType.SIZE);
   }
 
+  public boolean hasInterval()
+  {
+    return analysisTypes.contains(AnalysisType.INTERVAL);
+  }
+
   public byte[] getAnalysisTypesCacheKey()
   {
     int size = 1;
@@ -259,6 +266,10 @@ public class SegmentMetadataQuery extends BaseQuery<SegmentAnalysis>
     if (usingDefaultInterval != that.usingDefaultInterval) {
       return false;
     }
+
+    if (!analysisTypes.equals(that.analysisTypes)) {
+      return false;
+    }
     return !(toInclude != null ? !toInclude.equals(that.toInclude) : that.toInclude != null);
 
   }
@@ -270,6 +281,7 @@ public class SegmentMetadataQuery extends BaseQuery<SegmentAnalysis>
     result = 31 * result + (toInclude != null ? toInclude.hashCode() : 0);
     result = 31 * result + (merge ? 1 : 0);
     result = 31 * result + (usingDefaultInterval ? 1 : 0);
+    result = 31 * result + analysisTypes.hashCode();
     return result;
   }
 }

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

@@ -54,7 +54,7 @@ public class SegmentMetadataQueryQueryToolChestTest
         new SegmentMetadataQueryQueryToolChest(null).getCacheStrategy(query);
 
     // Test cache key generation
-    byte[] expectedKey = {0x04, 0x01, (byte) 0xFF, 0x00, 0x01};
+    byte[] expectedKey = {0x04, 0x01, (byte) 0xFF, 0x00, 0x01, 0x02};
     byte[] actualKey = strategy.computeCacheKey(query);
     Assert.assertArrayEquals(expectedKey, actualKey);
 

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

@@ -1025,6 +1025,7 @@ public class RealtimePlumber implements Plumber
 
         final File persistedFile = indexMerger.persist(
             indexToPersist.getIndex(),
+            interval,
             new File(computePersistDir(schema, interval), String.valueOf(indexToPersist.getCount())),
             metaData,
             indexSpec

server/src/test/java/io/druid/segment/realtime/plumber/RealtimePlumberSchoolTest.java

@@ -396,21 +396,23 @@ public class RealtimePlumberSchoolTest
     Map<Long, Sink> sinks = restoredPlumber.getSinks();
     Assert.assertEquals(1, sinks.size());
 
+
     List<FireHydrant> hydrants = Lists.newArrayList(sinks.get(new Long(0)));
     DateTime startTime = new DateTime("1970-01-01T00:00:00.000Z");
+    Interval expectedInterval = new Interval(startTime, new DateTime("1971-01-01T00:00:00.000Z"));
     Assert.assertEquals(0, hydrants.get(0).getCount());
     Assert.assertEquals(
-        new Interval(startTime, new DateTime("1970-01-01T00:00:00.001Z")),
+        expectedInterval,
         hydrants.get(0).getSegment().getDataInterval()
     );
     Assert.assertEquals(2, hydrants.get(1).getCount());
     Assert.assertEquals(
-        new Interval(startTime, new DateTime("1970-03-01T00:00:00.001Z")),
+        expectedInterval,
         hydrants.get(1).getSegment().getDataInterval()
     );
     Assert.assertEquals(4, hydrants.get(2).getCount());
     Assert.assertEquals(
-        new Interval(startTime, new DateTime("1970-05-01T00:00:00.001Z")),
+        expectedInterval,
         hydrants.get(2).getSegment().getDataInterval()
     );