LUCENE-5648: (NumberRangePrefixTree) Bug-fix in initIter optimization. Re-index required.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1602857 13f79535-47bb-0310-9956-ffa450edef68

lucene/spatial/src/java/org/apache/lucene/spatial/prefix/tree/NumberRangePrefixTree.java

@@ -96,17 +96,29 @@ public abstract class NumberRangePrefixTree extends SpatialPrefixTree {
   protected class NRShape implements Shape {
 
     private final LevelledValue minLV, maxLV;
+    private final int lastLevelInCommon;//computed; not part of identity
 
     /** Don't call directly; see {@link #toRangeShape(com.spatial4j.core.shape.Shape, com.spatial4j.core.shape.Shape)}. */
     private NRShape(LevelledValue minLV, LevelledValue maxLV) {
       this.minLV = minLV;
       this.maxLV = maxLV;
+
+      //calc lastLevelInCommon
+      int level = 1;
+      for (; level <= minLV.getLevel() && level <= maxLV.getLevel(); level++) {
+        if (minLV.getValAtLevel(level) != maxLV.getValAtLevel(level))
+          break;
+      }
+      lastLevelInCommon = level - 1;
     }
 
     public LevelledValue getMinLV() { return minLV; }
 
     public LevelledValue getMaxLV() { return maxLV; }
 
+    /** How many levels are in common between minLV and maxLV. */
+    private int getLastLevelInCommon() { return lastLevelInCommon; }
+
     @Override
     public SpatialRelation relate(Shape shape) {
 //      if (shape instanceof LevelledValue)
@@ -580,17 +592,22 @@ public abstract class NumberRangePrefixTree extends SpatialPrefixTree {
 
       final LevelledValue minLV;
       final LevelledValue maxLV;
+      final int lastLevelInCommon;//between minLV & maxLV
       if (filter instanceof NRShape) {
         NRShape nrShape = (NRShape) iterFilter;
         minLV = nrShape.getMinLV();
         maxLV = nrShape.getMaxLV();
+        lastLevelInCommon = nrShape.getLastLevelInCommon();
       } else {
         minLV = (LevelledValue) iterFilter;
         maxLV = minLV;
+        lastLevelInCommon = minLV.getLevel();
       }
 
-      //fast path check when using same filter
+      //fast path optimization that is usually true, but never first level
-      if (iterFilter == parent.iterFilter) {
+      if (iterFilter == parent.iterFilter &&
+          (getLevel() <= lastLevelInCommon || parent.iterFirstCellNumber != parent.iterLastCellNumber)) {
+        //TODO benchmark if this optimization pays off. We avoid two comparePrefixLV calls.
         if (parent.iterFirstIsIntersects && parent.cellNumber == parent.iterFirstCellNumber
             && minLV.getLevel() >= getLevel()) {
           iterFirstCellNumber = minLV.getValAtLevel(getLevel());
@@ -616,7 +633,7 @@ public abstract class NumberRangePrefixTree extends SpatialPrefixTree {
         return;
       }
 
-      //uncommon to get here, except for level 1 which always happens
+      //not common to get here, except for level 1 which always happens
 
       int startCmp = comparePrefixLV(minLV, parent);
       if (startCmp > 0) {//start comes after this cell
@@ -650,6 +667,12 @@ public abstract class NumberRangePrefixTree extends SpatialPrefixTree {
         iterLastCellNumber = maxLV.getValAtLevel(getLevel());
         iterLastIsIntersects = (maxLV.getLevel() > getLevel());
       }
+      if (iterFirstCellNumber == iterLastCellNumber) {
+        if (iterLastIsIntersects)
+          iterFirstIsIntersects = true;
+        else if (iterFirstIsIntersects)
+          iterLastIsIntersects = true;
+      }
     }
 
     @Override

lucene/spatial/src/test/org/apache/lucene/spatial/prefix/DateNRStrategyTest.java

@@ -91,6 +91,15 @@ public class DateNRStrategyTest extends BaseNonFuzzySpatialOpStrategyTest {
         tree.toShape(randomCalendar()), true);
   }
 
+  @Test
+  public void testBugInitIterOptimization() throws Exception {
+    //bug due to fast path initIter() optimization
+    testOperation(
+        tree.parseShape("[2014-03-27T23 TO 2014-04-01T01]"),
+        SpatialOperation.Intersects,
+        tree.parseShape("[2014-04 TO 2014-04-01T02]"), true);
+  }
+
   @Override
   protected Shape randomIndexedShape() {
     Calendar cal1 = randomCalendar();