Use the doc-values skip index to skip per-doc value lookups in LongRangeFacetCutter

lucene/CHANGES.txt

@@ -331,6 +331,9 @@ Optimizations
 
 * GITHUB#16352: Better cost() estimation for SkipBlockRangeIterator. (Alan Woodward)
 
+* GITHUB#16268: LongRangeFacetCutter: doc-values skip index for single + multi-valued fields,
+  single-valued segment unwrapping, and interval tracker rewind. (Jakub Slowinski)
+
 * GITHUB#16362: Add TwoPhaseIterator.applyMask() to support bulk matching for more
   expensive queries. (Alan Woodward)
 

lucene/sandbox/src/java/org/apache/lucene/sandbox/facet/cutters/ranges/IntervalTracker.java

@@ -36,6 +36,11 @@ interface IntervalTracker extends OrdinalIterator {
   /** clear recorded information on this tracker. * */
   void clear();
 
+  /**
+   * restart reading from the first recorded ordinal, to replay a {@link #freeze() frozen} tracker
+   */
+  void rewind();
+
   /** check if any data for the interval has been recorded * */
   boolean get(int index);
 
@@ -71,6 +76,12 @@ public void clear() {
       intervalsWithHit = 0;
     }
 
+    @Override
+    public void rewind() {
+      bitFrom = 0;
+      trackerState = 0;
+    }
+
     @Override
     public boolean get(int index) {
       return tracker.get(index);