Fixed the deserialization issue to ensure that vectors created using …

…string are correctly de-searilized

Signed-off-by: Navneet Verma <navneev@amazon.com>

src/main/java/org/opensearch/knn/index/codec/util/KNNCodecUtil.java

@@ -5,22 +5,22 @@
 
 package org.opensearch.knn.index.codec.util;
 
-import lombok.AllArgsConstructor;
-import lombok.Getter;
-import lombok.Setter;
-import lombok.extern.log4j.Log4j2;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
 import org.apache.lucene.index.BinaryDocValues;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.util.BytesRef;
-import org.opensearch.common.StopWatch;
 import org.opensearch.knn.index.KNNSettings;
 import org.opensearch.knn.index.codec.KNN80Codec.KNN80BinaryDocValues;
 import org.opensearch.knn.jni.JNICommons;
 
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+import lombok.extern.log4j.Log4j2;
 
 @Log4j2
 public class KNNCodecUtil {
@@ -61,27 +61,29 @@ public static KNNCodecUtil.Pair getFloats(BinaryDocValues values) throws IOExcep
             BytesRef bytesref = values.binaryValue();
             try (ByteArrayInputStream byteStream = new ByteArrayInputStream(bytesref.bytes, bytesref.offset, bytesref.length)) {
                 final float[] vector;
-                StopWatch stopWatch = new StopWatch();
-                stopWatch.start();
-                if (isVectorRepresentedAsString(bytesref)) {
-                    String vectorString = new String(bytesref.bytes, 1, bytesref.bytes.length - 1);
+                char firstChar = (char) (byteStream.read());
+                // resetting as we have just read all the bytes
+                byteStream.reset();
+                if (isVectorRepresentedAsString(firstChar)) {
+                    String vectorString = new String(byteStream.readAllBytes());
                     String[] array = vectorString.split(",");
                     vector = new float[array.length];
                     try {
                         for (int i = 0; i < array.length; i++) {
+                            if (i == 0) {
+                                array[i] = array[i].substring(1, array[i].length());
+                            }
                             vector[i] = Float.parseFloat(array[i]);
                         }
                     } catch (Exception e) {
-                        log.error("Error while converting floats for str: {}", vectorString, e);
+                        log.error("Vector String: {}", vectorString);
+                        // log.error("Error while converting floats for str: {}", vectorString, e);
                     }
-                    stopWatch.stop();
-                    log.info("Time taken to deserialize vector with string is : {} ms", stopWatch.totalTime().millis());
                 } else {
+
                     serializationMode = KNNVectorSerializerFactory.serializerModeFromStream(byteStream);
                     final KNNVectorSerializer vectorSerializer = KNNVectorSerializerFactory.getSerializerByStreamContent(byteStream);
                     vector = vectorSerializer.byteToFloatArray(byteStream);
-                    stopWatch.stop();
-                    log.info("Time taken to deserialize vector with float array is : {} ms", stopWatch.totalTime().millis());
                 }
                 dimension = vector.length;
 
@@ -149,8 +151,9 @@ private static long getTotalLiveDocsCount(final BinaryDocValues binaryDocValues)
         return totalLiveDocs;
     }
 
-    private static boolean isVectorRepresentedAsString(BytesRef bytesref) {
+    private static boolean isVectorRepresentedAsString(char firstChar) {
         // Check if first bye is the special character that we have added or not.
-        return "N".equals(new String(bytesref.bytes, 0, 1));
+        char n = 'N';
+        return n == firstChar;
     }
 }