elastic · thecoop · Oct 14, 2025
diff --git a/server/src/main/java/module-info.java b/server/src/main/java/module-info.java
@@ -465,6 +465,7 @@
             org.elasticsearch.index.codec.vectors.diskbbq.ES920DiskBBQVectorsFormat,
             org.elasticsearch.index.codec.vectors.diskbbq.next.ESNextDiskBBQVectorsFormat,
             org.elasticsearch.index.codec.vectors.es93.ES93BinaryQuantizedVectorsFormat,
+            org.elasticsearch.index.codec.vectors.es93.ES93HnswVectorsFormat,
             org.elasticsearch.index.codec.vectors.es93.ES93HnswBinaryQuantizedVectorsFormat;
 
     provides org.apache.lucene.codecs.Codec

diff --git a/...c/main/java/org/elasticsearch/index/codec/vectors/es93/ES93BFloat16FlatVectorsWriter.java b/...c/main/java/org/elasticsearch/index/codec/vectors/es93/ES93BFloat16FlatVectorsWriter.java
@@ -23,7 +23,6 @@
 import org.apache.lucene.codecs.hnsw.FlatFieldVectorsWriter;
 import org.apache.lucene.codecs.hnsw.FlatVectorsScorer;
 import org.apache.lucene.codecs.hnsw.FlatVectorsWriter;
-import org.apache.lucene.codecs.lucene95.OffHeapFloatVectorValues;
 import org.apache.lucene.codecs.lucene95.OrdToDocDISIReaderConfiguration;
 import org.apache.lucene.index.DocsWithFieldSet;
 import org.apache.lucene.index.FieldInfo;
@@ -250,7 +249,7 @@ public CloseableRandomVectorScorerSupplier mergeOneFieldToIndex(FieldInfo fieldI
             final IndexInput finalVectorDataInput = vectorDataInput;
             final RandomVectorScorerSupplier randomVectorScorerSupplier = vectorsScorer.getRandomVectorScorerSupplier(
                 fieldInfo.getVectorSimilarityFunction(),
-                new OffHeapFloatVectorValues.DenseOffHeapVectorValues(
+                new OffHeapBFloat16VectorValues.DenseOffHeapVectorValues(
                     fieldInfo.getVectorDimension(),
                     docsWithField.cardinality(),
                     finalVectorDataInput,

diff --git a/server/src/main/java/org/elasticsearch/index/codec/vectors/es93/ES93HnswVectorsFormat.java b/server/src/main/java/org/elasticsearch/index/codec/vectors/es93/ES93HnswVectorsFormat.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.index.codec.vectors.es93;
+
+import org.apache.lucene.codecs.KnnVectorsReader;
+import org.apache.lucene.codecs.KnnVectorsWriter;
+import org.apache.lucene.codecs.hnsw.FlatVectorsFormat;
+import org.apache.lucene.codecs.lucene99.Lucene99HnswVectorsReader;
+import org.apache.lucene.codecs.lucene99.Lucene99HnswVectorsWriter;
+import org.apache.lucene.index.SegmentReadState;
+import org.apache.lucene.index.SegmentWriteState;
+import org.elasticsearch.index.codec.vectors.AbstractHnswVectorsFormat;
+
+import java.io.IOException;
+import java.util.concurrent.ExecutorService;
+
+public class ES93HnswVectorsFormat extends AbstractHnswVectorsFormat {
+
+    static final String NAME = "ES93HnswVectorsFormat";
+
+    private final FlatVectorsFormat flatVectorsFormat;
+
+    public ES93HnswVectorsFormat() {
+        super(NAME);
+        flatVectorsFormat = new ES93GenericFlatVectorsFormat();
+    }
+
+    public ES93HnswVectorsFormat(int maxConn, int beamWidth, boolean bfloat16, boolean useDirectIO) {
+        super(NAME, maxConn, beamWidth);
+        flatVectorsFormat = new ES93GenericFlatVectorsFormat(bfloat16, useDirectIO);
+    }
+
+    public ES93HnswVectorsFormat(
+        int maxConn,
+        int beamWidth,
+        boolean bfloat16,
+        boolean useDirectIO,
+        int numMergeWorkers,
+        ExecutorService mergeExec
+    ) {
+        super(NAME, maxConn, beamWidth, numMergeWorkers, mergeExec);
+        flatVectorsFormat = new ES93GenericFlatVectorsFormat(bfloat16, useDirectIO);
+    }
+
+    @Override
+    protected FlatVectorsFormat flatVectorsFormat() {
+        return flatVectorsFormat;
+    }
+
+    @Override
+    public KnnVectorsWriter fieldsWriter(SegmentWriteState state) throws IOException {
+        return new Lucene99HnswVectorsWriter(state, maxConn, beamWidth, flatVectorsFormat.fieldsWriter(state), numMergeWorkers, mergeExec);
+    }
+
+    @Override
+    public KnnVectorsReader fieldsReader(SegmentReadState state) throws IOException {
+        return new Lucene99HnswVectorsReader(state, flatVectorsFormat.fieldsReader(state));
+    }
+}
diff --git a/server/src/main/resources/META-INF/services/org.apache.lucene.codecs.KnnVectorsFormat b/server/src/main/resources/META-INF/services/org.apache.lucene.codecs.KnnVectorsFormat
@@ -10,4 +10,5 @@ org.elasticsearch.index.codec.vectors.es818.ES818HnswBinaryQuantizedVectorsForma
 org.elasticsearch.index.codec.vectors.diskbbq.ES920DiskBBQVectorsFormat
 org.elasticsearch.index.codec.vectors.diskbbq.next.ESNextDiskBBQVectorsFormat
 org.elasticsearch.index.codec.vectors.es93.ES93BinaryQuantizedVectorsFormat
+org.elasticsearch.index.codec.vectors.es93.ES93HnswVectorsFormat
 org.elasticsearch.index.codec.vectors.es93.ES93HnswBinaryQuantizedVectorsFormat
diff --git a/...t/java/org/elasticsearch/index/codec/vectors/es93/ES93HnswBFloat16VectorsFormatTests.java b/...t/java/org/elasticsearch/index/codec/vectors/es93/ES93HnswBFloat16VectorsFormatTests.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.index.codec.vectors.es93;
+
+import org.apache.lucene.index.VectorEncoding;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static org.hamcrest.Matchers.closeTo;
+
+public class ES93HnswBFloat16VectorsFormatTests extends ES93HnswVectorsFormatTests {
+
+    @Override
+    protected boolean useBFloat16() {
+        return true;
+    }
+
+    @Override
+    protected VectorEncoding randomVectorEncoding() {
+        return VectorEncoding.FLOAT32;
+    }
+
+    @Override
+    public void testEmptyByteVectorData() throws Exception {
+        // no bytes
+    }
+
+    @Override
+    public void testMergingWithDifferentByteKnnFields() throws Exception {
+        // no bytes
+    }
+
+    @Override
+    public void testByteVectorScorerIteration() throws Exception {
+        // no bytes
+    }
+
+    @Override
+    public void testSortedIndexBytes() throws Exception {
+        // no bytes
+    }
+
+    @Override
+    public void testMismatchedFields() throws Exception {
+        // no bytes
+    }
+
+    @Override
+    public void testRandomBytes() throws Exception {
+        // no bytes
+    }
+
+    @Override
+    public void testRandom() throws Exception {
+        AssertionError err = expectThrows(AssertionError.class, super::testRandom);
+        assertFloatsWithinBounds(err);
+    }
+
+    @Override
+    public void testRandomWithUpdatesAndGraph() throws Exception {
+        AssertionError err = expectThrows(AssertionError.class, super::testRandomWithUpdatesAndGraph);
+        assertFloatsWithinBounds(err);
+    }
+
+    @Override
+    public void testSparseVectors() throws Exception {
+        AssertionError err = expectThrows(AssertionError.class, super::testSparseVectors);
+        assertFloatsWithinBounds(err);
+    }
+
+    @Override
+    public void testVectorValuesReportCorrectDocs() throws Exception {
+        AssertionError err = expectThrows(AssertionError.class, super::testVectorValuesReportCorrectDocs);
+        assertFloatsWithinBounds(err);
+    }
+
+    private static final Pattern FLOAT_ASSERTION_FAILURE = Pattern.compile(".*expected:<([0-9.-]+)> but was:<([0-9.-]+)>");
+
+    private static void assertFloatsWithinBounds(AssertionError error) {
+        Matcher m = FLOAT_ASSERTION_FAILURE.matcher(error.getMessage());
+        if (m.matches() == false) {
+            throw error;    // nothing to do with us, just rethrow
+        }
+
+        // numbers just need to be in the same vicinity
+        double expected = Double.parseDouble(m.group(1));
+        double actual = Double.parseDouble(m.group(2));
+        double allowedError = expected * 0.01;  // within 1%
+        assertThat(error.getMessage(), actual, closeTo(expected, allowedError));
+    }
+}
diff --git a/.../src/test/java/org/elasticsearch/index/codec/vectors/es93/ES93HnswVectorsFormatTests.java b/.../src/test/java/org/elasticsearch/index/codec/vectors/es93/ES93HnswVectorsFormatTests.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.index.codec.vectors.es93;
+
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.codecs.FilterCodec;
+import org.apache.lucene.codecs.KnnVectorsFormat;
+import org.apache.lucene.codecs.KnnVectorsReader;
+import org.apache.lucene.codecs.perfield.PerFieldKnnVectorsFormat;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.KnnFloatVectorField;
+import org.apache.lucene.index.CodecReader;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.index.BaseKnnVectorsFormatTestCase;
+import org.apache.lucene.tests.util.TestUtil;
+import org.apache.lucene.util.SameThreadExecutorService;
+import org.elasticsearch.common.logging.LogConfigurator;
+import org.elasticsearch.index.codec.vectors.BFloat16;
+
+import java.io.IOException;
+import java.util.Locale;
+
+import static java.lang.String.format;
+import static org.apache.lucene.codecs.lucene99.Lucene99HnswVectorsFormat.DEFAULT_BEAM_WIDTH;
+import static org.apache.lucene.codecs.lucene99.Lucene99HnswVectorsFormat.DEFAULT_MAX_CONN;
+import static org.apache.lucene.index.VectorSimilarityFunction.DOT_PRODUCT;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.oneOf;
+
+public class ES93HnswVectorsFormatTests extends BaseKnnVectorsFormatTestCase {
+
+    static {
+        LogConfigurator.loadLog4jPlugins();
+        LogConfigurator.configureESLogging(); // native access requires logging to be initialized
+    }
+
+    private KnnVectorsFormat format;
+
+    protected boolean useBFloat16() {
+        return false;
+    }
+
+    @Override
+    public void setUp() throws Exception {
+        format = new ES93HnswVectorsFormat(DEFAULT_MAX_CONN, DEFAULT_BEAM_WIDTH, useBFloat16(), random().nextBoolean());
+        super.setUp();
+    }
+
+    @Override
+    protected Codec getCodec() {
+        return TestUtil.alwaysKnnVectorsFormat(format);
+    }
+
+    public void testToString() {
+        FilterCodec customCodec = new FilterCodec("foo", Codec.getDefault()) {
+            @Override
+            public KnnVectorsFormat knnVectorsFormat() {
+                return new ES93HnswVectorsFormat(10, 20, false, false);
+            }
+        };
+        String expectedPattern = "ES93HnswVectorsFormat(name=ES93HnswVectorsFormat, maxConn=10, beamWidth=20,"
+            + " flatVectorFormat=ES93GenericFlatVectorsFormat(name=ES93GenericFlatVectorsFormat,"
+            + " format=Lucene99FlatVectorsFormat(name=Lucene99FlatVectorsFormat, flatVectorScorer=%s())))";
+        var defaultScorer = format(Locale.ROOT, expectedPattern, "DefaultFlatVectorScorer");
+        var memSegScorer = format(Locale.ROOT, expectedPattern, "Lucene99MemorySegmentFlatVectorsScorer");
+        assertThat(customCodec.knnVectorsFormat().toString(), is(oneOf(defaultScorer, memSegScorer)));
+    }
+
+    public void testLimits() {
+        expectThrows(IllegalArgumentException.class, () -> new ES93HnswVectorsFormat(-1, 20, false, false));
+        expectThrows(IllegalArgumentException.class, () -> new ES93HnswVectorsFormat(0, 20, false, false));
+        expectThrows(IllegalArgumentException.class, () -> new ES93HnswVectorsFormat(20, 0, false, false));
+        expectThrows(IllegalArgumentException.class, () -> new ES93HnswVectorsFormat(20, -1, false, false));
+        expectThrows(IllegalArgumentException.class, () -> new ES93HnswVectorsFormat(512 + 1, 20, false, false));
+        expectThrows(IllegalArgumentException.class, () -> new ES93HnswVectorsFormat(20, 3201, false, false));
+        expectThrows(
+            IllegalArgumentException.class,
+            () -> new ES93HnswVectorsFormat(20, 100, false, false, 1, new SameThreadExecutorService())
+        );
+    }
+
+    public void testSimpleOffHeapSize() throws IOException {
+        float[] vector = randomVector(random().nextInt(12, 500));
+        try (Directory dir = newDirectory(); IndexWriter w = new IndexWriter(dir, newIndexWriterConfig())) {
+            Document doc = new Document();
+            doc.add(new KnnFloatVectorField("f", vector, DOT_PRODUCT));
+            w.addDocument(doc);
+            w.commit();
+            try (IndexReader reader = DirectoryReader.open(w)) {
+                LeafReader r = getOnlyLeafReader(reader);
+                if (r instanceof CodecReader codecReader) {
+                    KnnVectorsReader knnVectorsReader = codecReader.getVectorReader();
+                    if (knnVectorsReader instanceof PerFieldKnnVectorsFormat.FieldsReader fieldsReader) {
+                        knnVectorsReader = fieldsReader.getFieldReader("f");
+                    }
+                    var fieldInfo = r.getFieldInfos().fieldInfo("f");
+                    var offHeap = knnVectorsReader.getOffHeapByteSize(fieldInfo);
+                    int bytes = useBFloat16() ? BFloat16.BYTES : Float.BYTES;
+                    assertEquals(vector.length * bytes, (long) offHeap.get("vec"));
+                    assertEquals(1L, (long) offHeap.get("vex"));
+                    assertEquals(2, offHeap.size());
+                }
+            }
+        }
+    }
+}