Skip EnhancedAttributeValue wrapping in converters transformTo when t… (#6707)

* Skip EnhancedAttributeValue wrapping in converters transformTo when type is already correct

* Add isolated benchmarks for converters

* Fix benchmark mode

* Remove unusued benchmark

* Add changelog

---------

Co-authored-by: RanVaknin <>

Author: RanVaknin

.changes/next-release/feature-AmazonDynamoDBEnhancedClient-9637599.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "Amazon DynamoDB Enhanced Client",
+    "contributor": "",
+    "description": "Improved performance by adding a fast path avoiding wrapping of String and Byte types"
+}

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/converter/attribute/ByteArrayAttributeConverter.java

@@ -69,7 +69,7 @@ public AttributeValue transformFrom(byte[] input) {
     @Override
     public byte[] transformTo(AttributeValue input) {
         if (input.b() != null) {
-            return EnhancedAttributeValue.fromBytes(input.b()).convert(VISITOR);
+            return input.b().asByteArray();
         }
 
         return EnhancedAttributeValue.fromAttributeValue(input).convert(VISITOR);

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/converter/attribute/StringAttributeConverter.java

@@ -70,7 +70,10 @@ public AttributeValue transformFrom(String input) {
 
     @Override
     public String transformTo(AttributeValue input) {
-        return Visitor.toString(input);
+        if (input.s() != null) {
+            return input.s();
+        }
+        return EnhancedAttributeValue.fromAttributeValue(input).convert(Visitor.INSTANCE);
     }
 
     private static final class Visitor extends TypeConvertingVisitor<String> {