Restored fast path for NumPy

Author: ankane

pgvector/psycopg/vector.py

@@ -28,9 +28,7 @@ class VectorBinaryDumper(VectorDumper):
     format = Format.BINARY
 
     def dump(self, obj: 'Vector | np.ndarray') -> Buffer | None:
-        if not isinstance(obj, Vector):
-            obj = Vector(obj)
-        return obj.to_binary()
+        return Vector._to_db_binary(obj)
 
 
 class VectorLoader(Loader):

pgvector/vector.py

@@ -86,6 +86,16 @@ def _to_db_binary(cls, value: object) -> bytes | None:
         if value is None:
             return value
 
+        # fast path for NumPy
+        if NUMPY_AVAILABLE and isinstance(value, np.ndarray):
+            if value.ndim != 1:
+                raise ValueError('expected ndim to be 1')
+
+            if value.dtype != '>f4':
+                value = np.asarray(value, dtype='>f4')
+
+            return struct.pack('>HH', len(value), 0) + value.tobytes()
+
         if not isinstance(value, cls):
             value = cls(value)  # type: ignore