Fix bytes offset bug and duplicate readers and add uTs for derived source

src/main/java/org/opensearch/knn/index/codec/KNN9120Codec/DerivedSourceStoredFieldsFormat.java

@@ -19,6 +19,7 @@
 import org.opensearch.index.mapper.MappedFieldType;
 import org.opensearch.index.mapper.MapperService;
 import org.opensearch.knn.index.KNNSettings;
+import org.opensearch.knn.index.codec.derivedsource.DerivedSourceReaders;
 import org.opensearch.knn.index.codec.derivedsource.DerivedSourceReadersSupplier;
 import org.opensearch.knn.index.mapper.KNNVectorFieldType;
 
@@ -55,11 +56,14 @@ public StoredFieldsReader fieldsReader(Directory directory, SegmentInfo segmentI
         if (derivedVectorFields == null || derivedVectorFields.isEmpty()) {
             return delegate.fieldsReader(directory, segmentInfo, fieldInfos, ioContext);
         }
+
+        SegmentReadState segmentReadState = new SegmentReadState(directory, segmentInfo, fieldInfos, ioContext);
+        DerivedSourceReaders derivedSourceReaders = derivedSourceReadersSupplier.getReaders(segmentReadState);
         return new DerivedSourceStoredFieldsReader(
             delegate.fieldsReader(directory, segmentInfo, fieldInfos, ioContext),
             derivedVectorFields,
-            derivedSourceReadersSupplier,
-            new SegmentReadState(directory, segmentInfo, fieldInfos, ioContext)
+            derivedSourceReaders,
+            segmentReadState
         );
     }
 

src/main/java/org/opensearch/knn/index/codec/KNN9120Codec/DerivedSourceStoredFieldsReader.java

@@ -5,23 +5,25 @@
 
 package org.opensearch.knn.index.codec.KNN9120Codec;
 
+import lombok.extern.log4j.Log4j2;
 import org.apache.lucene.codecs.StoredFieldsReader;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.SegmentReadState;
 import org.apache.lucene.index.StoredFieldVisitor;
 import org.apache.lucene.util.IOUtils;
 import org.opensearch.index.fieldvisitor.FieldsVisitor;
-import org.opensearch.knn.index.codec.derivedsource.DerivedSourceReadersSupplier;
+import org.opensearch.knn.index.codec.derivedsource.DerivedSourceReaders;
 import org.opensearch.knn.index.codec.derivedsource.DerivedSourceStoredFieldVisitor;
 import org.opensearch.knn.index.codec.derivedsource.DerivedSourceVectorInjector;
 
 import java.io.IOException;
 import java.util.List;
 
+@Log4j2
 public class DerivedSourceStoredFieldsReader extends StoredFieldsReader {
     private final StoredFieldsReader delegate;
     private final List<FieldInfo> derivedVectorFields;
-    private final DerivedSourceReadersSupplier derivedSourceReadersSupplier;
+    private final DerivedSourceReaders derivedSourceReaders;
     private final SegmentReadState segmentReadState;
     private final boolean shouldInject;
 
@@ -31,36 +33,36 @@ public class DerivedSourceStoredFieldsReader extends StoredFieldsReader {
      *
      * @param delegate delegate StoredFieldsReader
      * @param derivedVectorFields List of fields that are derived source fields
-     * @param derivedSourceReadersSupplier Supplier for the derived source readers
+     * @param derivedSourceReaders Derived source readers
      * @param segmentReadState SegmentReadState for the segment
      * @throws IOException in case of I/O error
      */
     public DerivedSourceStoredFieldsReader(
         StoredFieldsReader delegate,
         List<FieldInfo> derivedVectorFields,
-        DerivedSourceReadersSupplier derivedSourceReadersSupplier,
+        DerivedSourceReaders derivedSourceReaders,
         SegmentReadState segmentReadState
     ) throws IOException {
-        this(delegate, derivedVectorFields, derivedSourceReadersSupplier, segmentReadState, true);
+        this(delegate, derivedVectorFields, derivedSourceReaders, segmentReadState, true);
     }
 
     private DerivedSourceStoredFieldsReader(
         StoredFieldsReader delegate,
         List<FieldInfo> derivedVectorFields,
-        DerivedSourceReadersSupplier derivedSourceReadersSupplier,
+        DerivedSourceReaders derivedSourceReaders,
         SegmentReadState segmentReadState,
         boolean shouldInject
     ) throws IOException {
         this.delegate = delegate;
         this.derivedVectorFields = derivedVectorFields;
-        this.derivedSourceReadersSupplier = derivedSourceReadersSupplier;
+        this.derivedSourceReaders = derivedSourceReaders;
         this.segmentReadState = segmentReadState;
         this.shouldInject = shouldInject;
         this.derivedSourceVectorInjector = createDerivedSourceVectorInjector();
     }
 
-    private DerivedSourceVectorInjector createDerivedSourceVectorInjector() throws IOException {
-        return new DerivedSourceVectorInjector(derivedSourceReadersSupplier, segmentReadState, derivedVectorFields);
+    private DerivedSourceVectorInjector createDerivedSourceVectorInjector() {
+        return new DerivedSourceVectorInjector(derivedSourceReaders, segmentReadState, derivedVectorFields);
     }
 
     @Override
@@ -86,7 +88,7 @@ public StoredFieldsReader clone() {
             return new DerivedSourceStoredFieldsReader(
                 delegate.clone(),
                 derivedVectorFields,
-                derivedSourceReadersSupplier,
+                derivedSourceReaders.clone(),
                 segmentReadState,
                 shouldInject
             );
@@ -102,6 +104,7 @@ public void checkIntegrity() throws IOException {
 
     @Override
     public void close() throws IOException {
+        log.debug("Closing derived source stored fields reader for segment: " + segmentReadState.segmentInfo.name);
         IOUtils.close(delegate, derivedSourceVectorInjector);
     }
 
@@ -117,7 +120,7 @@ private StoredFieldsReader cloneForMerge() {
             return new DerivedSourceStoredFieldsReader(
                 delegate.getMergeInstance(),
                 derivedVectorFields,
-                derivedSourceReadersSupplier,
+                derivedSourceReaders.clone(),
                 segmentReadState,
                 false
             );

src/main/java/org/opensearch/knn/index/codec/KNN9120Codec/DerivedSourceStoredFieldsWriter.java

@@ -79,7 +79,7 @@ public void writeField(FieldInfo fieldInfo, BytesRef bytesRef) throws IOExceptio
             // Reference:
             // https://github.com/opensearch-project/OpenSearch/blob/2.18.0/server/src/main/java/org/opensearch/index/mapper/SourceFieldMapper.java#L322
             Tuple<? extends MediaType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(
-                BytesReference.fromByteBuffer(ByteBuffer.wrap(bytesRef.bytes)),
+                BytesReference.fromByteBuffer(ByteBuffer.wrap(bytesRef.bytes, bytesRef.offset, bytesRef.length)),
                 true,
                 MediaTypeRegistry.JSON
             );

src/main/java/org/opensearch/knn/index/codec/KNN9120Codec/KNN9120Codec.java

@@ -25,6 +25,7 @@ public class KNN9120Codec extends FilterCodec {
     private static final KNNCodecVersion VERSION = KNNCodecVersion.V_9_12_0;
     private final KNNFormatFacade knnFormatFacade;
     private final PerFieldKnnVectorsFormat perFieldKnnVectorsFormat;
+    private final StoredFieldsFormat storedFieldsFormat;
 
     private final MapperService mapperService;
 
@@ -48,6 +49,7 @@ protected KNN9120Codec(Codec delegate, PerFieldKnnVectorsFormat knnVectorsFormat
         knnFormatFacade = VERSION.getKnnFormatFacadeSupplier().apply(delegate);
         perFieldKnnVectorsFormat = knnVectorsFormat;
         this.mapperService = mapperService;
+        this.storedFieldsFormat = getStoredFieldsFormat();
     }
 
     @Override
@@ -67,6 +69,10 @@ public KnnVectorsFormat knnVectorsFormat() {
 
     @Override
     public StoredFieldsFormat storedFieldsFormat() {
+        return storedFieldsFormat;
+    }
+
+    private StoredFieldsFormat getStoredFieldsFormat() {
         DerivedSourceReadersSupplier derivedSourceReadersSupplier = new DerivedSourceReadersSupplier((segmentReadState) -> {
             if (segmentReadState.fieldInfos.hasVectorValues()) {
                 return knnVectorsFormat().fieldsReader(segmentReadState);

src/main/java/org/opensearch/knn/index/codec/derivedsource/DerivedSourceReaders.java

@@ -7,6 +7,7 @@
 
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.log4j.Log4j2;
 import org.apache.lucene.codecs.DocValuesProducer;
 import org.apache.lucene.codecs.FieldsProducer;
 import org.apache.lucene.codecs.KnnVectorsReader;
@@ -23,7 +24,8 @@
  */
 @RequiredArgsConstructor
 @Getter
-public class DerivedSourceReaders implements Closeable {
+@Log4j2
+public class DerivedSourceReaders implements Cloneable, Closeable {
     @Nullable
     private final KnnVectorsReader knnVectorsReader;
     @Nullable
@@ -33,8 +35,17 @@ public class DerivedSourceReaders implements Closeable {
     @Nullable
     private final NormsProducer normsProducer;
 
+    private final boolean isCloned;
+
     @Override
     public void close() throws IOException {
-        IOUtils.close(knnVectorsReader, docValuesProducer, fieldsProducer, normsProducer);
+        if (isCloned == false) {
+            IOUtils.close(knnVectorsReader, docValuesProducer, fieldsProducer, normsProducer);
+        }
+    }
+
+    @Override
+    public DerivedSourceReaders clone() {
+        return new DerivedSourceReaders(knnVectorsReader, docValuesProducer, fieldsProducer, normsProducer, true);
     }
 }

src/main/java/org/opensearch/knn/index/codec/derivedsource/DerivedSourceReadersSupplier.java

@@ -27,7 +27,7 @@ public class DerivedSourceReadersSupplier {
     private final DerivedSourceReaderSupplier<NormsProducer> normsProducer;
 
     /**
-     * Get the readers for the segment
+     * Get the readers for the segment.
      *
      * @param state SegmentReadState
      * @return DerivedSourceReaders
@@ -38,7 +38,8 @@ public DerivedSourceReaders getReaders(SegmentReadState state) throws IOExceptio
             knnVectorsReaderSupplier.apply(state),
             docValuesProducerSupplier.apply(state),
             fieldsProducerSupplier.apply(state),
-            normsProducer.apply(state)
+            normsProducer.apply(state),
+            false
         );
     }
 }

src/main/java/org/opensearch/knn/index/codec/derivedsource/DerivedSourceVectorInjector.java

@@ -42,16 +42,16 @@ public class DerivedSourceVectorInjector implements Closeable {
     /**
      * Constructor for DerivedSourceVectorInjector.
      *
-     * @param derivedSourceReadersSupplier Supplier for the derived source readers.
+     * @param derivedSourceReaders Derived source readers.
      * @param segmentReadState Segment read state
      * @param fieldsToInjectVector List of fields to inject vectors into
      */
     public DerivedSourceVectorInjector(
-        DerivedSourceReadersSupplier derivedSourceReadersSupplier,
+        DerivedSourceReaders derivedSourceReaders,
         SegmentReadState segmentReadState,
         List<FieldInfo> fieldsToInjectVector
-    ) throws IOException {
-        this.derivedSourceReaders = derivedSourceReadersSupplier.getReaders(segmentReadState);
+    ) {
+        this.derivedSourceReaders = derivedSourceReaders;
         this.perFieldDerivedVectorInjectors = new ArrayList<>();
         this.fieldNames = new HashSet<>();
         for (FieldInfo fieldInfo : fieldsToInjectVector) {

src/main/java/org/opensearch/knn/index/codec/derivedsource/ParentChildHelper.java

@@ -15,9 +15,12 @@ public class ParentChildHelper {
      * this would return "parent.to".
      *
      * @param field nested field path
-     * @return parent field path without the child
+     * @return parent field path without the child. Null if no parent exists
      */
     public static String getParentField(String field) {
+        if (field == null) {
+            return null;
+        }
         int lastDot = field.lastIndexOf('.');
         if (lastDot == -1) {
             return null;
@@ -30,10 +33,16 @@ public static String getParentField(String field) {
      * return "child".
      *
      * @param field nested field path
-     * @return child field path without the parent path
+     * @return child field path without the parent path. Null if no child exists
      */
     public static String getChildField(String field) {
+        if (field == null) {
+            return null;
+        }
         int lastDot = field.lastIndexOf('.');
+        if (lastDot == -1) {
+            return null;
+        }
         return field.substring(lastDot + 1);
     }
 
@@ -46,7 +55,11 @@ public static String getChildField(String field) {
      * @return sibling field path
      */
     public static String constructSiblingField(String field, String sibling) {
-        return getParentField(field) + "." + sibling;
+        String parent = getParentField(field);
+        if (parent == null) {
+            return sibling;
+        }
+        return parent + "." + sibling;
     }
 
     /**

src/main/java/org/opensearch/knn/index/vectorvalues/VectorValueExtractorStrategy.java

@@ -20,7 +20,7 @@
 /**
  * Provides different strategies to extract the vectors from different {@link KNNVectorValuesIterator}
  */
-interface VectorValueExtractorStrategy {
+public interface VectorValueExtractorStrategy {
 
     /**
      * Extract a float vector from KNNVectorValuesIterator.

src/test/java/org/opensearch/knn/index/codec/KNN9120Codec/DerivedSourceStoredFieldsWriterTests.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.knn.index.codec.KNN9120Codec;
+
+import lombok.SneakyThrows;
+import org.apache.lucene.codecs.StoredFieldsWriter;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.util.BytesRef;
+import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.knn.KNNTestCase;
+import org.opensearch.knn.index.codec.KNNCodecTestUtil;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.mockito.Mockito.mock;
+
+public class DerivedSourceStoredFieldsWriterTests extends KNNTestCase {
+
+    @SneakyThrows
+    public void testWriteField() {
+        StoredFieldsWriter delegate = mock(StoredFieldsWriter.class);
+        FieldInfo fieldInfo = KNNCodecTestUtil.FieldInfoBuilder.builder("_source").build();
+        List<String> fields = List.of("test");
+
+        DerivedSourceStoredFieldsWriter derivedSourceStoredFieldsWriter = new DerivedSourceStoredFieldsWriter(delegate, fields);
+
+        Map<String, Object> source = Map.of("test", new float[] { 1.0f, 2.0f, 3.0f }, "text_field", "text_value");
+        BytesStreamOutput bStream = new BytesStreamOutput();
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(MediaTypeRegistry.JSON, bStream).map(source);
+        builder.close();
+        byte[] originalBytes = bStream.bytes().toBytesRef().bytes;
+        byte[] shiftedBytes = new byte[originalBytes.length + 2];
+        System.arraycopy(originalBytes, 0, shiftedBytes, 1, originalBytes.length);
+        derivedSourceStoredFieldsWriter.writeField(fieldInfo, new BytesRef(shiftedBytes, 1, originalBytes.length));
+    }
+}

src/test/java/org/opensearch/knn/index/codec/derivedsource/DerivedSourceStoredFieldVisitorTests.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.knn.index.codec.derivedsource;
+
+import org.apache.lucene.index.StoredFieldVisitor;
+import org.opensearch.knn.KNNTestCase;
+import org.opensearch.knn.index.codec.KNNCodecTestUtil;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class DerivedSourceStoredFieldVisitorTests extends KNNTestCase {
+
+    public void testBinaryField() throws Exception {
+        StoredFieldVisitor delegate = mock(StoredFieldVisitor.class);
+        doAnswer(invocationOnMock -> null).when(delegate).binaryField(any(), any());
+        DerivedSourceVectorInjector derivedSourceVectorInjector = mock(DerivedSourceVectorInjector.class);
+        when(derivedSourceVectorInjector.injectVectors(anyInt(), any())).thenReturn(new byte[0]);
+        DerivedSourceStoredFieldVisitor derivedSourceStoredFieldVisitor = new DerivedSourceStoredFieldVisitor(
+            delegate,
+            0,
+            derivedSourceVectorInjector
+        );
+
+        // When field is not _source, then do not call the injector
+        derivedSourceStoredFieldVisitor.binaryField(KNNCodecTestUtil.FieldInfoBuilder.builder("test").build(), null);
+        verify(derivedSourceVectorInjector, times(0)).injectVectors(anyInt(), any());
+        verify(delegate, times(1)).binaryField(any(), any());
+
+        // When field is not _source, then do call the injector
+        derivedSourceStoredFieldVisitor.binaryField(KNNCodecTestUtil.FieldInfoBuilder.builder("_source").build(), null);
+        verify(derivedSourceVectorInjector, times(1)).injectVectors(anyInt(), any());
+        verify(delegate, times(2)).binaryField(any(), any());
+    }
+}