keep serialized tensor in TensorFieldValue

* do lazy deserialization in getTensor() and getTensorType()
* avoid re-serializing when forwarding a TensorFieldValue

4 files changed, 61 insertions, 17 deletions

diff --git a/document/abi-spec.json b/document/abi-spec.json
index df1fb840cbc..4a94d7e55de 100644
--- a/document/abi-spec.json
+++ b/document/abi-spec.json
@@ -3164,6 +3164,8 @@
       "public void printXml(com.yahoo.document.serialization.XmlStream)",
       "public void clear()",
       "public void assign(java.lang.Object)",
+      "public void assignSerializedTensor(byte[])",
+      "public java.util.Optional getSerializedTensor()",
       "public void assignTensor(java.util.Optional)",
       "public void serialize(com.yahoo.document.Field, com.yahoo.document.serialization.FieldWriter)",
       "public void deserialize(com.yahoo.document.Field, com.yahoo.document.serialization.FieldReader)",
@@ -4471,4 +4473,4 @@
       "protected com.yahoo.document.update.ValueUpdate$ValueUpdateClassID valueUpdateClassID"
     ]
   }
-}
\ No newline at end of file
+}
diff --git a/document/src/main/java/com/yahoo/document/datatypes/TensorFieldValue.java b/document/src/main/java/com/yahoo/document/datatypes/TensorFieldValue.java
index 8e7dbd3512a..3177ec54465 100644
--- a/document/src/main/java/com/yahoo/document/datatypes/TensorFieldValue.java
+++ b/document/src/main/java/com/yahoo/document/datatypes/TensorFieldValue.java
@@ -6,8 +6,10 @@ import com.yahoo.document.TensorDataType;
 import com.yahoo.document.serialization.FieldReader;
 import com.yahoo.document.serialization.FieldWriter;
 import com.yahoo.document.serialization.XmlStream;
+import com.yahoo.io.GrowableByteBuffer;
 import com.yahoo.tensor.Tensor;
 import com.yahoo.tensor.TensorType;
+import com.yahoo.tensor.serialization.TypedBinaryFormat;
 
 import java.util.Optional;
 
@@ -20,6 +22,8 @@ public class TensorFieldValue extends FieldValue {
 
     private Optional<Tensor> tensor;
 
+    private Optional<byte[]> serializedTensor;
+
     private Optional<TensorDataType> dataType;
 
     /**
@@ -28,27 +32,49 @@ public class TensorFieldValue extends FieldValue {
      * The tensor (and tensor type) can later be assigned with assignTensor().
      */
     public TensorFieldValue() {
-       this.dataType = Optional.empty();
-       this.tensor = Optional.empty();
+        this.dataType = Optional.empty();
+        this.serializedTensor = Optional.empty();
+        this.tensor = Optional.empty();
     }
 
     /** Create an empty tensor field value for the given tensor type */
     public TensorFieldValue(TensorType type) {
         this.dataType = Optional.of(new TensorDataType(type));
+        this.serializedTensor = Optional.empty();
         this.tensor = Optional.empty();
     }
 
     /** Create a tensor field value containing the given tensor */
     public TensorFieldValue(Tensor tensor) {
         this.dataType = Optional.of(new TensorDataType(tensor.type()));
+        this.serializedTensor = Optional.empty();
         this.tensor = Optional.of(tensor);
     }
 
+    private void lazyDeserialize() {
+        if (tensor.isEmpty() && serializedTensor.isPresent()) {
+            Tensor t = TypedBinaryFormat.decode(Optional.empty(), GrowableByteBuffer.wrap(serializedTensor.get()));
+            if (dataType.isEmpty()) {
+                this.dataType = Optional.of(new TensorDataType(t.type()));
+                this.tensor = Optional.of(t);
+            } else {
+                if (t.type().isAssignableTo(dataType.get().getTensorType())) {
+                    this.tensor = Optional.of(t);
+                } else {
+                    throw new IllegalArgumentException("Type mismatch: Cannot assign tensor of type " + t.type() +
+                                                       " to field of type " + dataType.get());
+                }
+            }
+        }
+    }
+
     public Optional<Tensor> getTensor() {
+        lazyDeserialize();
         return tensor;
     }
 
     public Optional<TensorType> getTensorType() {
+        lazyDeserialize();
         return dataType.isPresent() ? Optional.of(dataType.get().getTensorType()) : Optional.empty();
     }
 
@@ -59,8 +85,9 @@ public class TensorFieldValue extends FieldValue {
 
     @Override
     public String toString() {
-        if (tensor.isPresent()) {
-            return tensor.get().toString();
+        var t = getTensor();
+        if (t.isPresent()) {
+            return t.get().toString();
         } else {
             return "null";
         }
@@ -74,6 +101,7 @@ public class TensorFieldValue extends FieldValue {
     @Override
     public void clear() {
         tensor = Optional.empty();
+        serializedTensor = Optional.empty();
     }
 
     @Override
@@ -90,12 +118,28 @@ public class TensorFieldValue extends FieldValue {
         }
     }
 
+    public void assignSerializedTensor(byte[] data) {
+        serializedTensor = Optional.of(data);
+        tensor = Optional.empty();
+    }
+
+    public Optional<byte[]> getSerializedTensor() {
+        if (serializedTensor.isPresent()) {
+            return serializedTensor;
+        } else if (tensor.isPresent()) {
+            serializedTensor = Optional.of(TypedBinaryFormat.encode(tensor.get()));
+            assert(serializedTensor.isPresent());
+        }
+        return serializedTensor;
+    }
+
     /**
      * Assigns the given tensor to this field value.
      *
      * The tensor type is also set from the given tensor if it was not set before.
      */
     public void assignTensor(Optional<Tensor> tensor) {
+        this.serializedTensor = Optional.empty();
         if (tensor.isPresent()) {
             if (getTensorType().isPresent() &&
                     !tensor.get().type().isAssignableTo(getTensorType().get())) {
@@ -126,7 +170,7 @@ public class TensorFieldValue extends FieldValue {
 
         TensorFieldValue other = (TensorFieldValue)o;
         if ( ! getTensorType().equals(other.getTensorType())) return false;
-        if ( ! tensor.equals(other.tensor)) return false;
+        if ( ! getTensor().equals(other.getTensor())) return false;
         return true;
     }
 
@@ -136,4 +180,3 @@ public class TensorFieldValue extends FieldValue {
     }
 
 }
-
diff --git a/document/src/main/java/com/yahoo/document/serialization/VespaDocumentDeserializer6.java b/document/src/main/java/com/yahoo/document/serialization/VespaDocumentDeserializer6.java
index 92b3b566b85..914f0ad8759 100644
--- a/document/src/main/java/com/yahoo/document/serialization/VespaDocumentDeserializer6.java
+++ b/document/src/main/java/com/yahoo/document/serialization/VespaDocumentDeserializer6.java
@@ -97,7 +97,7 @@ public class VespaDocumentDeserializer6 extends BufferSerializer implements Docu
     final public DocumentTypeManager getDocumentTypeManager() { return manager; }
 
     public void read(Document document) {
-         read(null, document);
+        read(null, document);
     }
 
     @SuppressWarnings("deprecation")
@@ -243,8 +243,7 @@ public class VespaDocumentDeserializer6 extends BufferSerializer implements Docu
         int encodedTensorLength = buf.getInt1_4Bytes();
         if (encodedTensorLength > 0) {
             byte[] encodedTensor = getBytes(null, encodedTensorLength);
-            value.assign(TypedBinaryFormat.decode(value.getTensorType(),
-                                                  GrowableByteBuffer.wrap(encodedTensor)));
+            value.assignSerializedTensor(encodedTensor);
         } else {
             value.clear();
         }
@@ -374,9 +373,9 @@ public class VespaDocumentDeserializer6 extends BufferSerializer implements Docu
             Integer f_id = fieldIdsAndLengths.get(i).first;
             Field structField = priType.getField(f_id);
             if (structField != null) {
-              FieldValue value = structField.getDataType().createFieldValue();
-              value.deserialize(structField, this);
-              primary.setFieldValue(structField, value);
+                FieldValue value = structField.getDataType().createFieldValue();
+                value.deserialize(structField, this);
+                primary.setFieldValue(structField, value);
             }
             //jump to beginning of next field:
             position(posBefore + fieldIdsAndLengths.get(i).second.intValue());
diff --git a/document/src/main/java/com/yahoo/document/serialization/VespaDocumentSerializer6.java b/document/src/main/java/com/yahoo/document/serialization/VespaDocumentSerializer6.java
index 3fca853b4d1..1a5c5c8257b 100644
--- a/document/src/main/java/com/yahoo/document/serialization/VespaDocumentSerializer6.java
+++ b/document/src/main/java/com/yahoo/document/serialization/VespaDocumentSerializer6.java
@@ -290,10 +290,10 @@ public class VespaDocumentSerializer6 extends BufferSerializer implements Docume
 
     @Override
     public void write(FieldBase field, TensorFieldValue value) {
-        if (value.getTensor().isPresent()) {
-            byte[] encodedTensor = TypedBinaryFormat.encode(value.getTensor().get());
-            buf.putInt1_4Bytes(encodedTensor.length);
-            buf.put(encodedTensor);
+        var encodedTensor = value.getSerializedTensor();
+        if (encodedTensor.isPresent()) {
+            buf.putInt1_4Bytes(encodedTensor.get().length);
+            buf.put(encodedTensor.get());
         } else {
             buf.putInt1_4Bytes(0);
         }