Use DocIdSetBuilder instead of RoaringDocIdSet.Builder for DocIdSet c…

…onstruction.

Switch to simpler DocIdSetBuilder that use much less memory in common case.
Benchmarks show that in common case it aslo brings increase of throughput.

community/lucene-index/src/main/java/org/neo4j/kernel/api/impl/index/collector/DocValuesCollector.java

@@ -39,7 +39,7 @@
 import org.apache.lucene.search.TopFieldCollector;
 import org.apache.lucene.search.TopScoreDocCollector;
 import org.apache.lucene.util.ArrayUtil;
-import org.apache.lucene.util.RoaringDocIdSet;
+import org.apache.lucene.util.DocIdSetBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -511,11 +511,11 @@ public NumericDocValues readDocValues( String field )
      */
     private static final class Docs
     {
-        private final RoaringDocIdSet.Builder bits;
+        private final DocIdSetBuilder bits;
 
         public Docs( int maxDoc )
         {
-            bits = new RoaringDocIdSet.Builder( maxDoc );
+            bits = new DocIdSetBuilder( maxDoc );
         }
 
         /** Record the given document. */

community/lucene-index/src/test/java/org/neo4j/kernel/api/impl/index/IndexReaderStub.java

@@ -19,6 +19,7 @@
  */
 package org.neo4j.kernel.api.impl.index;
 
+import org.apache.commons.lang3.math.NumberUtils;
 import org.apache.lucene.index.BinaryDocValues;
 import org.apache.lucene.index.DocValues;
 import org.apache.lucene.index.DocValuesType;
@@ -36,10 +37,13 @@
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 
+import static com.sun.corba.se.spi.activation.IIOP_CLEAR_TEXT.value;
+
 public class IndexReaderStub extends LeafReader
 {
 
@@ -201,7 +205,7 @@ public int numDocs()
     @Override
     public int maxDoc()
     {
-        return elements.length;
+        return Math.max( maxValue(), elements.length) + 1;
     }
 
     @Override
@@ -214,4 +218,10 @@ public void document( int docID, StoredFieldVisitor visitor ) throws IOException
     protected void doClose() throws IOException
     {
     }
+
+    private int maxValue()
+    {
+        return Arrays.stream( elements )
+                .mapToInt( value ->  NumberUtils.toInt( value, 0 )).max().getAsInt();
+    }
 }