Avoid unnecessary DisjunctionMaxBulkScorer overhead

lucene/CHANGES.txt

@@ -342,6 +342,10 @@ Optimizations
 * GITHUB#15607: Utilize bulk scoring for diversity checking when building HNSW vector indices. This results
   in some performance improvements during indexing and segment merges. (Ben Trent)
 
+* GITHUB#15658: DisjunctionMaxBulkScorer now uses progressive window sizing sub-scorers to be skipped
+  sooner when their scores are no longer competitive (Shimpei Kodama)
+
+
 Bug Fixes
 ---------------------
 * GITHUB#14161: PointInSetQuery's constructor now throws IllegalArgumentException

lucene/core/src/java/org/apache/lucene/search/DisjunctionMaxBulkScorer.java

@@ -46,6 +46,7 @@ private static class BulkScorerAndNext {
   private final float[] windowScores = new float[WINDOW_SIZE];
   private final PriorityQueue<BulkScorerAndNext> scorers;
   private final SimpleScorable topLevelScorable = new SimpleScorable();
+  private int currentWindowSize = 1;
 
   DisjunctionMaxBulkScorer(List<BulkScorer> scorers) {
     if (scorers.size() < 2) {
@@ -64,7 +65,7 @@ public int score(LeafCollector collector, Bits acceptDocs, int min, int max) thr
 
     while (top.next < max) {
       final int windowMin = Math.max(top.next, min);
-      final int windowMax = MathUtil.unsignedMin(max, windowMin + WINDOW_SIZE);
+      final int windowMax = MathUtil.unsignedMin(max, windowMin + currentWindowSize);
 
       // First compute matches / scores in the window
       do {
@@ -105,6 +106,10 @@ public void collect(int doc) throws IOException {
         collector.collect(doc);
       }
 
+      if (currentWindowSize < WINDOW_SIZE) {
+        currentWindowSize = Math.min(currentWindowSize << 1, WINDOW_SIZE);
+      }
+
       // Finally clean up state
       windowMatches.clear();
       Arrays.fill(windowScores, 0f);