Revert "allocate one NeighborQueue per search for results (#12255)"

This reverts commit 9a7efe9.
apache · May 18, 2023 · 2facb3a · 2facb3a
1 parent 0c6e8ae
commit 2facb3a
Showing 1 changed file with 12 additions and 23 deletions.
diff --git a/lucene/core/src/java/org/apache/lucene/util/hnsw/HnswGraphSearcher.java b/lucene/core/src/java/org/apache/lucene/util/hnsw/HnswGraphSearcher.java
@@ -100,7 +100,7 @@ public static NeighborQueue search(
             similarityFunction,
             new NeighborQueue(topK, true),
             new SparseFixedBitSet(vectors.size()));
-    NeighborQueue results = new NeighborQueue(topK, false);
+    NeighborQueue results;
 
     int initialEp = graph.entryNode();
     if (initialEp == -1) {
@@ -109,8 +109,7 @@ public static NeighborQueue search(
     int[] eps = new int[] {initialEp};
     int numVisited = 0;
     for (int level = graph.numLevels() - 1; level >= 1; level--) {
-      results.clear();
-      graphSearcher.searchLevel(results, query, 1, level, eps, vectors, graph, null, visitedLimit);
+      results = graphSearcher.searchLevel(query, 1, level, eps, vectors, graph, null, visitedLimit);
       numVisited += results.visitedCount();
       visitedLimit -= results.visitedCount();
       if (results.incomplete()) {
@@ -119,9 +118,8 @@ public static NeighborQueue search(
       }
       eps[0] = results.pop();
     }
-    results.clear();
-    graphSearcher.searchLevel(
-        results, query, topK, 0, eps, vectors, graph, acceptOrds, visitedLimit);
+    results =
+        graphSearcher.searchLevel(query, topK, 0, eps, vectors, graph, acceptOrds, visitedLimit);
     results.setVisitedCount(results.visitedCount() + numVisited);
     return results;
   }
@@ -163,12 +161,11 @@ public static NeighborQueue search(
             similarityFunction,
             new NeighborQueue(topK, true),
             new SparseFixedBitSet(vectors.size()));
-    NeighborQueue results = new NeighborQueue(topK, false);
+    NeighborQueue results;
     int[] eps = new int[] {graph.entryNode()};
     int numVisited = 0;
     for (int level = graph.numLevels() - 1; level >= 1; level--) {
-      results.clear();
-      graphSearcher.searchLevel(results, query, 1, level, eps, vectors, graph, null, visitedLimit);
+      results = graphSearcher.searchLevel(query, 1, level, eps, vectors, graph, null, visitedLimit);
 
       numVisited += results.visitedCount();
       visitedLimit -= results.visitedCount();
@@ -179,9 +176,8 @@ public static NeighborQueue search(
       }
       eps[0] = results.pop();
     }
-    results.clear();
-    graphSearcher.searchLevel(
-        results, query, topK, 0, eps, vectors, graph, acceptOrds, visitedLimit);
+    results =
+        graphSearcher.searchLevel(query, topK, 0, eps, vectors, graph, acceptOrds, visitedLimit);
     results.setVisitedCount(results.visitedCount() + numVisited);
     return results;
   }
@@ -209,19 +205,10 @@ public NeighborQueue searchLevel(
       RandomAccessVectorValues<T> vectors,
       HnswGraph graph)
       throws IOException {
-    NeighborQueue results = new NeighborQueue(topK, false);
-    searchLevel(results, query, topK, level, eps, vectors, graph, null, Integer.MAX_VALUE);
-    return results;
+    return searchLevel(query, topK, level, eps, vectors, graph, null, Integer.MAX_VALUE);
   }
 
-  /**
-   * Add the closest neighbors found to a priority queue (heap). These are returned in REVERSE
-   * proximity order -- the most distant neighbor of the topK found, i.e. the one with the lowest
-   * score/comparison value, will be at the top of the heap, while the closest neighbor will be the
-   * last to be popped.
-   */
-  private void searchLevel(
-      NeighborQueue results,
+  private NeighborQueue searchLevel(
       T query,
       int topK,
       int level,
@@ -232,6 +219,7 @@ private void searchLevel(
       int visitedLimit)
       throws IOException {
     int size = graph.size();
+    NeighborQueue results = new NeighborQueue(topK, false);
     prepareScratchState(vectors.size());
 
     int numVisited = 0;
@@ -292,6 +280,7 @@ private void searchLevel(
       results.pop();
     }
     results.setVisitedCount(numVisited);
+    return results;
   }
 
   private float compare(T query, RandomAccessVectorValues<T> vectors, int ord) throws IOException {