Fix few bugs on binary index with Faiss HNSW

Signed-off-by: Heemin Kim <heemin@amazon.com>

src/main/java/org/opensearch/knn/index/IndexUtil.java

@@ -190,6 +190,14 @@ public static ValidationException validateKnnField(
             return exception;
         }
 
+        String vectorDataType = (String) fieldMap.get(VECTOR_DATA_TYPE_FIELD);
+        if (VectorDataType.BINARY.toString().equalsIgnoreCase(vectorDataType)) {
+            exception.addValidationError(
+                String.format(Locale.ROOT, "Field \"%s\" is of data type %s. Only FLOAT or BYTE is supported.", field, VectorDataType.BINARY)
+            );
+            return exception;
+        }
+
         // Return if dimension does not need to be checked
         if (expectedDimension < 0) {
             return null;

src/main/java/org/opensearch/knn/index/KNNMethod.java

@@ -22,6 +22,7 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
@@ -57,8 +58,10 @@ public ValidationException validate(KNNMethodContext knnMethodContext) {
         if (!isSpaceTypeSupported(knnMethodContext.getSpaceType())) {
             errorMessages.add(
                 String.format(
-                    "\"%s\" configuration does not support space type: " + "\"%s\".",
+                    Locale.ROOT,
+                    "\"%s\" with \"%s\" configuration does not support space type: " + "\"%s\".",
                     this.methodComponent.getName(),
+                    knnMethodContext.getKnnEngine().getName().toLowerCase(Locale.ROOT),
                     knnMethodContext.getSpaceType().getValue()
                 )
             );
@@ -90,8 +93,10 @@ public ValidationException validateWithData(KNNMethodContext knnMethodContext, V
         if (!isSpaceTypeSupported(knnMethodContext.getSpaceType())) {
             errorMessages.add(
                 String.format(
-                    "\"%s\" configuration does not support space type: " + "\"%s\".",
+                    Locale.ROOT,
+                    "\"%s\" with \"%s\" configuration does not support space type: " + "\"%s\".",
                     this.methodComponent.getName(),
+                    knnMethodContext.getKnnEngine().getName().toLowerCase(Locale.ROOT),
                     knnMethodContext.getSpaceType().getValue()
                 )
             );

src/main/java/org/opensearch/knn/index/KNNSettings.java

@@ -86,6 +86,7 @@ public class KNNSettings {
      */
     public static final boolean KNN_DEFAULT_FAISS_AVX2_DISABLED_VALUE = false;
     public static final String INDEX_KNN_DEFAULT_SPACE_TYPE = "l2";
+    public static final String INDEX_KNN_DEFAULT_SPACE_TYPE_FOR_BINARY = "hammingbit";
     public static final Integer INDEX_KNN_DEFAULT_ALGO_PARAM_M = 16;
     public static final Integer INDEX_KNN_DEFAULT_ALGO_PARAM_EF_SEARCH = 100;
     public static final Integer INDEX_KNN_DEFAULT_ALGO_PARAM_EF_CONSTRUCTION = 100;

src/main/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapper.java

@@ -307,7 +307,7 @@ public KNNVectorFieldMapper build(BuilderContext context) {
 
             // Build legacy
             if (this.spaceType == null) {
-                this.spaceType = LegacyFieldMapper.getSpaceType(context.indexSettings());
+                this.spaceType = LegacyFieldMapper.getSpaceType(context.indexSettings(), vectorDataType.getValue());
             }
 
             if (this.m == null) {

src/main/java/org/opensearch/knn/index/mapper/LegacyFieldMapper.java

@@ -12,6 +12,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.mapper.ParametrizedFieldMapper;
 import org.opensearch.knn.index.KNNSettings;
+import org.opensearch.knn.index.VectorDataType;
 import org.opensearch.knn.index.util.IndexHyperParametersUtil;
 import org.opensearch.knn.index.util.KNNEngine;
 
@@ -78,17 +79,19 @@ public ParametrizedFieldMapper.Builder getMergeBuilder() {
         );
     }
 
-    static String getSpaceType(Settings indexSettings) {
+    static String getSpaceType(final Settings indexSettings, final VectorDataType vectorDataType) {
         String spaceType = indexSettings.get(KNNSettings.INDEX_KNN_SPACE_TYPE.getKey());
         if (spaceType == null) {
+            spaceType = VectorDataType.BINARY == vectorDataType
+                ? KNNSettings.INDEX_KNN_DEFAULT_SPACE_TYPE_FOR_BINARY
+                : KNNSettings.INDEX_KNN_DEFAULT_SPACE_TYPE;
             log.info(
                 String.format(
                     "[KNN] The setting \"%s\" was not set for the index. Likely caused by recent version upgrade. Setting the setting to the default value=%s",
                     METHOD_PARAMETER_SPACE_TYPE,
-                    KNNSettings.INDEX_KNN_DEFAULT_SPACE_TYPE
+                    spaceType
                 )
             );
-            return KNNSettings.INDEX_KNN_DEFAULT_SPACE_TYPE;
         }
         return spaceType;
     }

src/main/java/org/opensearch/knn/index/query/KNNQueryBuilder.java

@@ -622,6 +622,11 @@ protected Query doToQuery(QueryShardContext context) {
                     String.format(Locale.ROOT, "Engine [%s] does not support radial search", knnEngine)
                 );
             }
+            if (vectorDataType == VectorDataType.BINARY) {
+                throw new UnsupportedOperationException(
+                    String.format(Locale.ROOT, "Binary data type does not support radial search")
+                );
+            }
             RNNQueryFactory.CreateQueryRequest createQueryRequest = RNNQueryFactory.CreateQueryRequest.builder()
                 .knnEngine(knnEngine)
                 .indexName(indexName)

src/main/java/org/opensearch/knn/index/query/KNNWeight.java

@@ -476,8 +476,15 @@ private boolean canDoExactSearch(final int filterIdsCount) {
         if (isExactSearchThresholdSettingSet(filterThresholdValue)) {
             return filterThresholdValue >= filterIdsCount;
         }
+
         // if no setting is set, then use the default max distance computation value to see if we can do exact search.
-        return KNNConstants.MAX_DISTANCE_COMPUTATIONS >= filterIdsCount * knnQuery.getQueryVector().length;
+        /**
+         * TODO we can have a different MAX_DISTANCE_COMPUTATIONS for binary index as computation cost for binary index
+         * is cheaper than computation cost for non binary vector
+         */
+        return KNNConstants.MAX_DISTANCE_COMPUTATIONS >= filterIdsCount * (knnQuery.getVectorDataType() == VectorDataType.FLOAT
+            ? knnQuery.getQueryVector().length
+            : knnQuery.getByteQueryVector().length);
     }
 
     /**

src/test/java/org/opensearch/knn/index/IndexUtilTests.java

@@ -228,6 +228,27 @@ public void testValidateKnnField_EmptyIndexMetadata() {
         assert (Objects.requireNonNull(e).getMessage().matches("Validation Failed: 1: Invalid index. Index does not contain a mapping;"));
     }
 
+    public void testValidateKnnField_whenBinaryDataType_thenThrowException() {
+        Map<String, Object> fieldValues = Map.of("type", "knn_vector", "dimension", 8, "data_type", "BINARY");
+        Map<String, Object> top_level_field = Map.of("top_level_field", fieldValues);
+        Map<String, Object> properties = Map.of("properties", top_level_field);
+        String field = "top_level_field";
+        int dimension = 8;
+
+        MappingMetadata mappingMetadata = mock(MappingMetadata.class);
+        when(mappingMetadata.getSourceAsMap()).thenReturn(properties);
+        IndexMetadata indexMetadata = mock(IndexMetadata.class);
+        when(indexMetadata.mapping()).thenReturn(mappingMetadata);
+        ModelDao modelDao = mock(ModelDao.class);
+        ModelMetadata trainingFieldModelMetadata = mock(ModelMetadata.class);
+        when(trainingFieldModelMetadata.getDimension()).thenReturn(dimension);
+        when(modelDao.getMetadata(anyString())).thenReturn(trainingFieldModelMetadata);
+
+        ValidationException e = IndexUtil.validateKnnField(indexMetadata, field, dimension, modelDao);
+
+        assert (Objects.requireNonNull(e).getMessage().contains("is of data type BINARY. Only FLOAT or BYTE is supported"));
+    }
+
     public void testIsShareableStateContainedInIndex_whenIndexNotModelBased_thenReturnFalse() {
         String modelId = null;
         KNNEngine knnEngine = KNNEngine.FAISS;

src/test/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapperTests.java

@@ -192,24 +192,38 @@ public void testBuilder_build_fromLegacy() {
         ModelDao modelDao = mock(ModelDao.class);
         KNNVectorFieldMapper.Builder builder = new KNNVectorFieldMapper.Builder("test-field-name-1", modelDao, CURRENT);
 
-        SpaceType spaceType = SpaceType.COSINESIMIL;
         int m = 17;
         int efConstruction = 17;
 
         // Setup settings
         Settings settings = Settings.builder()
             .put(settings(CURRENT).build())
-            .put(KNNSettings.KNN_SPACE_TYPE, spaceType.getValue())
             .put(KNNSettings.KNN_ALGO_PARAM_M, m)
             .put(KNNSettings.KNN_ALGO_PARAM_EF_CONSTRUCTION, efConstruction)
             .build();
 
         Mapper.BuilderContext builderContext = new Mapper.BuilderContext(settings, new ContentPath());
         KNNVectorFieldMapper knnVectorFieldMapper = builder.build(builderContext);
         assertTrue(knnVectorFieldMapper instanceof LegacyFieldMapper);
-
         assertNull(knnVectorFieldMapper.modelId);
         assertNull(knnVectorFieldMapper.knnMethod);
+        assertEquals(SpaceType.L2.getValue(), ((LegacyFieldMapper) knnVectorFieldMapper).spaceType);
+    }
+
+    public void testBuilder_whenKnnFalseWithBinary_thenSetHammingAsDefault() {
+        // Check legacy is picked up if model context and method context are not set
+        ModelDao modelDao = mock(ModelDao.class);
+        KNNVectorFieldMapper.Builder builder = new KNNVectorFieldMapper.Builder("test-field-name-1", modelDao, CURRENT);
+        builder.vectorDataType.setValue(VectorDataType.BINARY);
+        builder.dimension.setValue(8);
+
+        // Setup settings
+        Settings settings = Settings.builder().put(settings(CURRENT).build()).build();
+
+        Mapper.BuilderContext builderContext = new Mapper.BuilderContext(settings, new ContentPath());
+        KNNVectorFieldMapper knnVectorFieldMapper = builder.build(builderContext);
+        assertTrue(knnVectorFieldMapper instanceof LegacyFieldMapper);
+        assertEquals(SpaceType.HAMMING_BIT.getValue(), ((LegacyFieldMapper) knnVectorFieldMapper).spaceType);
     }
 
     public void testBuilder_parse_fromKnnMethodContext_luceneEngine() throws IOException {

src/test/java/org/opensearch/knn/index/query/KNNQueryBuilderTests.java

@@ -718,6 +718,30 @@ public void testDoToQuery_whenPassNegativeDistance_whenUnSupportedSpaceType_then
         expectThrows(IllegalArgumentException.class, () -> knnQueryBuilder.doToQuery(mockQueryShardContext));
     }
 
+    public void testDoToQuery_whenRadialSearchOnBinaryIndex_thenException() {
+        float[] queryVector = { 1.0f };
+        KNNQueryBuilder knnQueryBuilder = KNNQueryBuilder.builder()
+            .fieldName(FIELD_NAME)
+            .vector(queryVector)
+            .maxDistance(MAX_DISTANCE)
+            .build();
+        Index dummyIndex = new Index("dummy", "dummy");
+        QueryShardContext mockQueryShardContext = mock(QueryShardContext.class);
+        KNNVectorFieldMapper.KNNVectorFieldType mockKNNVectorField = mock(KNNVectorFieldMapper.KNNVectorFieldType.class);
+        when(mockQueryShardContext.index()).thenReturn(dummyIndex);
+        when(mockKNNVectorField.getDimension()).thenReturn(8);
+        when(mockKNNVectorField.getVectorDataType()).thenReturn(VectorDataType.BINARY);
+        when(mockQueryShardContext.fieldMapper(anyString())).thenReturn(mockKNNVectorField);
+        MethodComponentContext methodComponentContext = new MethodComponentContext(
+            org.opensearch.knn.common.KNNConstants.METHOD_HNSW,
+            ImmutableMap.of()
+        );
+        KNNMethodContext knnMethodContext = new KNNMethodContext(KNNEngine.FAISS, SpaceType.HAMMING_BIT, methodComponentContext);
+        when(mockKNNVectorField.getKnnMethodContext()).thenReturn(knnMethodContext);
+        Exception e = expectThrows(UnsupportedOperationException.class, () -> knnQueryBuilder.doToQuery(mockQueryShardContext));
+        assertTrue(e.getMessage().contains("Binary data type does not support radial search"));
+    }
+
     public void testDoToQuery_KnnQueryWithFilter_Lucene() throws Exception {
         // Given
         float[] queryVector = { 1.0f, 2.0f, 3.0f, 4.0f };

src/test/java/org/opensearch/knn/index/query/KNNWeightTests.java

@@ -863,6 +863,74 @@ public void testANNWithFilterQuery_whenExactSearchViaThresholdSetting_thenSucces
         assertTrue(Comparators.isInOrder(actualDocIds, Comparator.naturalOrder()));
     }
 
+    /**
+     * This test ensure that we do the exact search when threshold settings are correct and not using filteredIds<=K
+     * condition to do exact search on binary index
+     * FilteredIdThreshold: 10
+     * FilteredIdThresholdPct: 10%
+     * FilteredIdsCount: 6
+     * liveDocs : null, as there is no deleted documents
+     * MaxDoc: 100
+     * K : 1
+     */
+    @SneakyThrows
+    public void testANNWithFilterQuery_whenExactSearchViaThresholdSettingOnBinaryIndex_thenSuccess() {
+        knnSettingsMockedStatic.when(() -> KNNSettings.getFilteredExactSearchThreshold(INDEX_NAME)).thenReturn(10);
+        byte[] vector = new byte[] { 1, 3 };
+        int k = 1;
+        final int[] filterDocIds = new int[] { 0, 1, 2, 3, 4, 5 };
+
+        final LeafReaderContext leafReaderContext = mock(LeafReaderContext.class);
+        final SegmentReader reader = mock(SegmentReader.class);
+        when(leafReaderContext.reader()).thenReturn(reader);
+        when(reader.maxDoc()).thenReturn(100);
+        when(reader.getLiveDocs()).thenReturn(null);
+        final Weight filterQueryWeight = mock(Weight.class);
+        final Scorer filterScorer = mock(Scorer.class);
+        when(filterQueryWeight.scorer(leafReaderContext)).thenReturn(filterScorer);
+
+        when(filterScorer.iterator()).thenReturn(DocIdSetIterator.all(filterDocIds.length));
+
+        final KNNQuery query = new KNNQuery(FIELD_NAME, BYTE_QUERY_VECTOR, k, INDEX_NAME, FILTER_QUERY, null, VectorDataType.BINARY);
+
+        final float boost = (float) randomDoubleBetween(0, 10, true);
+        final KNNWeight knnWeight = new KNNWeight(query, boost, filterQueryWeight);
+        final Map<String, String> attributesMap = ImmutableMap.of(
+            KNN_ENGINE,
+            KNNEngine.FAISS.getName(),
+            SPACE_TYPE,
+            SpaceType.HAMMING_BIT.name(),
+            PARAMETERS,
+            String.format(Locale.ROOT, "{\"%s\":\"%s\"}", INDEX_DESCRIPTION_PARAMETER, "BHNSW32")
+        );
+        final FieldInfos fieldInfos = mock(FieldInfos.class);
+        final FieldInfo fieldInfo = mock(FieldInfo.class);
+        final BinaryDocValues binaryDocValues = mock(BinaryDocValues.class);
+        when(reader.getFieldInfos()).thenReturn(fieldInfos);
+        when(fieldInfos.fieldInfo(any())).thenReturn(fieldInfo);
+        when(fieldInfo.attributes()).thenReturn(attributesMap);
+        when(fieldInfo.getAttribute(SPACE_TYPE)).thenReturn(SpaceType.HAMMING_BIT.getValue());
+        when(fieldInfo.getName()).thenReturn(FIELD_NAME);
+        when(reader.getBinaryDocValues(FIELD_NAME)).thenReturn(binaryDocValues);
+        when(binaryDocValues.advance(0)).thenReturn(0);
+        BytesRef vectorByteRef = new BytesRef(vector);
+        when(binaryDocValues.binaryValue()).thenReturn(vectorByteRef);
+
+        final KNNScorer knnScorer = (KNNScorer) knnWeight.scorer(leafReaderContext);
+        assertNotNull(knnScorer);
+        final DocIdSetIterator docIdSetIterator = knnScorer.iterator();
+        assertNotNull(docIdSetIterator);
+        assertEquals(EXACT_SEARCH_DOC_ID_TO_SCORES.size(), docIdSetIterator.cost());
+
+        final List<Integer> actualDocIds = new ArrayList<>();
+        for (int docId = docIdSetIterator.nextDoc(); docId != NO_MORE_DOCS; docId = docIdSetIterator.nextDoc()) {
+            actualDocIds.add(docId);
+            assertEquals(BINARY_EXACT_SEARCH_DOC_ID_TO_SCORES.get(docId) * boost, knnScorer.score(), 0.01f);
+        }
+        assertEquals(docIdSetIterator.cost(), actualDocIds.size());
+        assertTrue(Comparators.isInOrder(actualDocIds, Comparator.naturalOrder()));
+    }
+
     @SneakyThrows
     public void testANNWithFilterQuery_whenEmptyFilterIds_thenReturnEarly() {
         final LeafReaderContext leafReaderContext = mock(LeafReaderContext.class);