Improve embedding retrieval performance (#2300)

Signed-off-by: yhmo <[email protected]>

pymilvus/client/abstract.py

@@ -591,7 +591,16 @@ def get_fields_by_range(
             dim, vectors = field.vectors.dim, field.vectors
             field_meta.vectors.dim = dim
             if dtype == DataType.FLOAT_VECTOR:
-                field2data[name] = vectors.float_vector.data[start * dim : end * dim], field_meta
+                if start == 0 and (end - start) * dim >= len(vectors.float_vector.data):
+                    # If the range equals to the lenth of ectors.float_vector.data, direct return
+                    # it to avoid a copy. This logic improves performance by 25% for the case
+                    # retrival 1536 dim embeddings with topk=16384.
+                    field2data[name] = vectors.float_vector.data, field_meta
+                else:
+                    field2data[name] = (
+                        vectors.float_vector.data[start * dim : end * dim],
+                        field_meta,
+                    )
                 continue
 
             if dtype == DataType.BINARY_VECTOR:

pymilvus/client/entity_helper.py

@@ -708,9 +708,13 @@ def check_append(field_data: Any):
             dim = field_data.vectors.dim
             if len(field_data.vectors.float_vector.data) >= index * dim:
                 start_pos, end_pos = index * dim, (index + 1) * dim
-                entity_row_data[field_data.field_name] = [
-                    np.single(x) for x in field_data.vectors.float_vector.data[start_pos:end_pos]
-                ]
+                # Here we use numpy.array to convert the float64 values to numpy.float32 values,
+                # and return a list of numpy.float32 to users
+                # By using numpy.array, performance improved by 60% for topk=16384 dim=1536 case.
+                arr = np.array(
+                    field_data.vectors.float_vector.data[start_pos:end_pos], dtype=np.float32
+                )
+                entity_row_data[field_data.field_name] = list(arr)
         elif field_data.type == DataType.BINARY_VECTOR:
             dim = field_data.vectors.dim
             if len(field_data.vectors.binary_vector) >= index * (dim // 8):