Add updateable random scorer interface for vector index building (#14181

)

As stated by @ChrisHegarty and @msokolov the amount of garbage we create during vector index creation is pretty astounding.

This adjusts the interface to allow an "Updateable" random vector interface (@msokolov 's idea if I remember correctly) and refactors the usage to keep it threadsafe.

lucene/CHANGES.txt

@@ -90,7 +90,11 @@ Optimizations
 * GITHUB#14133: Dense blocks of postings are now encoded as bit sets.
   (Adrien Grand)
 
-# GITHUB#14169: Optimize ContextQuery with big number of contexts. (Mayya Sharipova)
+* GITHUB#14169: Optimize ContextQuery with big number of contexts. (Mayya Sharipova)
+
+* GITHUB#14181: Add updateable random scorer interface for knn vector index building. This allows
+  for fewer objects to be created during indexing and simplifies internally used iterfaces.
+  (Ben Trent)
 
 Bug Fixes
 ---------------------

lucene/benchmark-jmh/src/java/org/apache/lucene/benchmark/jmh/VectorScorerBenchmark.java

@@ -35,6 +35,7 @@
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.hnsw.RandomVectorScorer;
 import org.apache.lucene.util.hnsw.RandomVectorScorerSupplier;
+import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 import org.openjdk.jmh.annotations.*;
 
 @BenchmarkMode(Mode.Throughput)
@@ -57,7 +58,7 @@ public class VectorScorerBenchmark {
   IndexInput in;
   KnnVectorValues vectorValues;
   byte[] vec1, vec2;
-  RandomVectorScorer scorer;
+  UpdateableRandomVectorScorer scorer;
 
   @Setup(Level.Iteration)
   public void init() throws IOException {
@@ -76,7 +77,8 @@ public void init() throws IOException {
     scorer =
         FlatVectorScorerUtil.getLucene99FlatVectorsScorer()
             .getRandomVectorScorerSupplier(DOT_PRODUCT, vectorValues)
-            .scorer(0);
+            .scorer();
+    scorer.setScoringOrdinal(0);
   }
 
   @TearDown

lucene/codecs/src/java/org/apache/lucene/codecs/bitvectors/FlatBitVectorsScorer.java

@@ -26,14 +26,14 @@
 import org.apache.lucene.util.VectorUtil;
 import org.apache.lucene.util.hnsw.RandomVectorScorer;
 import org.apache.lucene.util.hnsw.RandomVectorScorerSupplier;
+import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 
 /** A bit vector scorer for scoring byte vectors. */
 public class FlatBitVectorsScorer implements FlatVectorsScorer {
   @Override
   public RandomVectorScorerSupplier getRandomVectorScorerSupplier(
       VectorSimilarityFunction similarityFunction, KnnVectorValues vectorValues)
       throws IOException {
-    assert vectorValues instanceof ByteVectorValues;
     if (vectorValues instanceof ByteVectorValues byteVectorValues) {
       return new BitRandomVectorScorerSupplier(byteVectorValues);
     }
@@ -51,14 +51,13 @@ public RandomVectorScorer getRandomVectorScorer(
   public RandomVectorScorer getRandomVectorScorer(
       VectorSimilarityFunction similarityFunction, KnnVectorValues vectorValues, byte[] target)
       throws IOException {
-    assert vectorValues instanceof ByteVectorValues;
     if (vectorValues instanceof ByteVectorValues byteVectorValues) {
       return new BitRandomVectorScorer(byteVectorValues, target);
     }
     throw new IllegalArgumentException("vectorValues must be an instance of ByteVectorValues");
   }
 
-  static class BitRandomVectorScorer implements RandomVectorScorer {
+  static class BitRandomVectorScorer implements UpdateableRandomVectorScorer {
     private final ByteVectorValues vectorValues;
     private final int bitDimensions;
     private final byte[] query;
@@ -80,6 +79,11 @@ public int maxOrd() {
       return vectorValues.size();
     }
 
+    @Override
+    public void setScoringOrdinal(int node) throws IOException {
+      System.arraycopy(vectorValues.vectorValue(node), 0, query, 0, query.length);
+    }
+
     @Override
     public int ordToDoc(int ord) {
       return vectorValues.ordToDoc(ord);
@@ -93,24 +97,22 @@ public Bits getAcceptOrds(Bits acceptDocs) {
 
   static class BitRandomVectorScorerSupplier implements RandomVectorScorerSupplier {
     protected final ByteVectorValues vectorValues;
-    protected final ByteVectorValues vectorValues1;
-    protected final ByteVectorValues vectorValues2;
+    protected final ByteVectorValues targetVectors;
 
     public BitRandomVectorScorerSupplier(ByteVectorValues vectorValues) throws IOException {
       this.vectorValues = vectorValues;
-      this.vectorValues1 = vectorValues.copy();
-      this.vectorValues2 = vectorValues.copy();
+      this.targetVectors = vectorValues.copy();
     }
 
     @Override
-    public RandomVectorScorer scorer(int ord) throws IOException {
-      byte[] query = vectorValues1.vectorValue(ord);
-      return new BitRandomVectorScorer(vectorValues2, query);
+    public UpdateableRandomVectorScorer scorer() throws IOException {
+      byte[] query = new byte[vectorValues.dimension()];
+      return new BitRandomVectorScorer(vectorValues, query);
     }
 
     @Override
     public RandomVectorScorerSupplier copy() throws IOException {
-      return new BitRandomVectorScorerSupplier(vectorValues.copy());
+      return new BitRandomVectorScorerSupplier(vectorValues);
     }
   }
 

lucene/core/src/java/org/apache/lucene/codecs/hnsw/DefaultFlatVectorScorer.java

@@ -24,6 +24,7 @@
 import org.apache.lucene.index.VectorSimilarityFunction;
 import org.apache.lucene.util.hnsw.RandomVectorScorer;
 import org.apache.lucene.util.hnsw.RandomVectorScorerSupplier;
+import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 
 /**
  * Default implementation of {@link FlatVectorsScorer}.
@@ -89,24 +90,29 @@ public String toString() {
   /** RandomVectorScorerSupplier for bytes vector */
   private static final class ByteScoringSupplier implements RandomVectorScorerSupplier {
     private final ByteVectorValues vectors;
-    private final ByteVectorValues vectors1;
-    private final ByteVectorValues vectors2;
+    private final ByteVectorValues targetVectors;
     private final VectorSimilarityFunction similarityFunction;
 
     private ByteScoringSupplier(
         ByteVectorValues vectors, VectorSimilarityFunction similarityFunction) throws IOException {
       this.vectors = vectors;
-      vectors1 = vectors.copy();
-      vectors2 = vectors.copy();
+      targetVectors = vectors.copy();
       this.similarityFunction = similarityFunction;
     }
 
     @Override
-    public RandomVectorScorer scorer(int ord) {
-      return new RandomVectorScorer.AbstractRandomVectorScorer(vectors) {
+    public UpdateableRandomVectorScorer scorer() throws IOException {
+      byte[] vector = new byte[vectors.dimension()];
+      return new UpdateableRandomVectorScorer.AbstractUpdateableRandomVectorScorer(vectors) {
+
+        @Override
+        public void setScoringOrdinal(int node) throws IOException {
+          System.arraycopy(targetVectors.vectorValue(node), 0, vector, 0, vector.length);
+        }
+
         @Override
         public float score(int node) throws IOException {
-          return similarityFunction.compare(vectors1.vectorValue(ord), vectors2.vectorValue(node));
+          return similarityFunction.compare(vector, targetVectors.vectorValue(node));
         }
       };
     }
@@ -125,24 +131,28 @@ public String toString() {
   /** RandomVectorScorerSupplier for Float vector */
   private static final class FloatScoringSupplier implements RandomVectorScorerSupplier {
     private final FloatVectorValues vectors;
-    private final FloatVectorValues vectors1;
-    private final FloatVectorValues vectors2;
+    private final FloatVectorValues targetVectors;
     private final VectorSimilarityFunction similarityFunction;
 
     private FloatScoringSupplier(
         FloatVectorValues vectors, VectorSimilarityFunction similarityFunction) throws IOException {
       this.vectors = vectors;
-      vectors1 = vectors.copy();
-      vectors2 = vectors.copy();
+      targetVectors = vectors.copy();
       this.similarityFunction = similarityFunction;
     }
 
     @Override
-    public RandomVectorScorer scorer(int ord) {
-      return new RandomVectorScorer.AbstractRandomVectorScorer(vectors) {
+    public UpdateableRandomVectorScorer scorer() throws IOException {
+      float[] vector = new float[vectors.dimension()];
+      return new UpdateableRandomVectorScorer.AbstractUpdateableRandomVectorScorer(vectors) {
         @Override
         public float score(int node) throws IOException {
-          return similarityFunction.compare(vectors1.vectorValue(ord), vectors2.vectorValue(node));
+          return similarityFunction.compare(vector, targetVectors.vectorValue(node));
+        }
+
+        @Override
+        public void setScoringOrdinal(int node) throws IOException {
+          System.arraycopy(targetVectors.vectorValue(node), 0, vector, 0, vector.length);
         }
       };
     }

lucene/core/src/java/org/apache/lucene/codecs/hnsw/ScalarQuantizedVectorScorer.java

@@ -24,6 +24,7 @@
 import org.apache.lucene.util.VectorUtil;
 import org.apache.lucene.util.hnsw.RandomVectorScorer;
 import org.apache.lucene.util.hnsw.RandomVectorScorerSupplier;
+import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 import org.apache.lucene.util.quantization.QuantizedByteVectorValues;
 import org.apache.lucene.util.quantization.ScalarQuantizedVectorSimilarity;
 import org.apache.lucene.util.quantization.ScalarQuantizer;
@@ -147,11 +148,18 @@ private ScalarQuantizedRandomVectorScorerSupplier(
     }
 
     @Override
-    public RandomVectorScorer scorer(int ord) throws IOException {
+    public UpdateableRandomVectorScorer scorer() throws IOException {
       final QuantizedByteVectorValues vectorsCopy = values.copy();
-      final byte[] queryVector = values.vectorValue(ord);
-      final float queryOffset = values.getScoreCorrectionConstant(ord);
-      return new RandomVectorScorer.AbstractRandomVectorScorer(vectorsCopy) {
+      byte[] queryVector = new byte[values.dimension()];
+      return new UpdateableRandomVectorScorer.AbstractUpdateableRandomVectorScorer(vectorsCopy) {
+        float queryOffset = 0;
+
+        @Override
+        public void setScoringOrdinal(int node) throws IOException {
+          System.arraycopy(vectorsCopy.vectorValue(node), 0, queryVector, 0, queryVector.length);
+          queryOffset = vectorsCopy.getScoreCorrectionConstant(node);
+        }
+
         @Override
         public float score(int node) throws IOException {
           byte[] nodeVector = vectorsCopy.vectorValue(node);

lucene/core/src/java/org/apache/lucene/codecs/lucene99/Lucene99FlatVectorsWriter.java

@@ -52,8 +52,8 @@
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.apache.lucene.util.hnsw.CloseableRandomVectorScorerSupplier;
-import org.apache.lucene.util.hnsw.RandomVectorScorer;
 import org.apache.lucene.util.hnsw.RandomVectorScorerSupplier;
+import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 
 /**
  * Writes vector values to index segments.
@@ -507,8 +507,8 @@ static final class FlatCloseableRandomVectorScorerSupplier
     }
 
     @Override
-    public RandomVectorScorer scorer(int ord) throws IOException {
-      return supplier.scorer(ord);
+    public UpdateableRandomVectorScorer scorer() throws IOException {
+      return supplier.scorer();
     }
 
     @Override

lucene/core/src/java/org/apache/lucene/codecs/lucene99/Lucene99HnswVectorsWriter.java

@@ -57,6 +57,7 @@
 import org.apache.lucene.util.hnsw.NeighborArray;
 import org.apache.lucene.util.hnsw.OnHeapHnswGraph;
 import org.apache.lucene.util.hnsw.RandomVectorScorerSupplier;
+import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 import org.apache.lucene.util.packed.DirectMonotonicWriter;
 
 /**
@@ -561,6 +562,7 @@ private static class FieldWriter<T> extends KnnFieldVectorsWriter<T> {
     private int lastDocID = -1;
     private int node = 0;
     private final FlatFieldVectorsWriter<T> flatFieldVectorsWriter;
+    private UpdateableRandomVectorScorer scorer;
 
     @SuppressWarnings("unchecked")
     static FieldWriter<?> create(
@@ -616,6 +618,7 @@ static FieldWriter<?> create(
                         (List<float[]>) flatFieldVectorsWriter.getVectors(),
                         fieldInfo.getVectorDimension()));
           };
+      this.scorer = scorerSupplier.scorer();
       hnswGraphBuilder =
           HnswGraphBuilder.create(scorerSupplier, M, beamWidth, HnswGraphBuilder.randSeed);
       hnswGraphBuilder.setInfoStream(infoStream);
@@ -631,7 +634,8 @@ public void addValue(int docID, T vectorValue) throws IOException {
                 + "\" appears more than once in this document (only one value is allowed per field)");
       }
       flatFieldVectorsWriter.addValue(docID, vectorValue);
-      hnswGraphBuilder.addGraphNode(node);
+      scorer.setScoringOrdinal(node);
+      hnswGraphBuilder.addGraphNode(node, scorer);
       node++;
       lastDocID = docID;
     }