pre-generate initial pypika query object per model, as it is immutable

tortoise/__init__.py

@@ -206,6 +206,12 @@ def _get_config_from_config_file(cls, config_file):
             )
         return config
 
+    @classmethod
+    def _build_initial_querysets(cls):
+        for app_name, app in cls.apps.items():
+            for model_name, model in app.items():
+                model._meta.basequery = model._meta.db.query_class.from_(model._meta.table)
+
     @classmethod
     async def init(
             cls,
@@ -303,6 +309,8 @@ async def init(
 
         cls._init_relations()
 
+        cls._build_initial_querysets()
+
         cls._inited = True
 
     @classmethod

tortoise/models.py

@@ -218,7 +218,8 @@ def get_filters_for_field(field_name: str, field: Optional[fields.Field], source
 class MetaInfo:
     __slots__ = ('abstract', 'table', 'app', 'fields', 'db_fields', 'm2m_fields', 'fk_fields',
                  'backward_fk_fields', 'fetch_fields', 'fields_db_projection', '_inited',
-                 'fields_db_projection_reverse', 'filters', 'fields_map', 'default_connection')
+                 'fields_db_projection_reverse', 'filters', 'fields_map', 'default_connection',
+                 'basequery')
 
     def __init__(self, meta):
         self.abstract = getattr(meta, 'abstract', False)  # type: bool
@@ -236,6 +237,7 @@ def __init__(self, meta):
         self.fields_map = {}  # type: Dict[str, fields.Field]
         self._inited = False
         self.default_connection = None
+        self.basequery = None
 
     @property
     def db(self):

tortoise/queryset.py

@@ -142,11 +142,7 @@ def __init__(self, model) -> None:
         self.fields = model._meta.db_fields
         self.model = model
 
-        if not hasattr(model._meta.db, 'query_class'):
-            # do not build Query if Tortoise wasn't inited
-            self.query = None
-        else:
-            self.query = model._meta.db.query_class.from_(model._meta.table)
+        self.query = model._meta.basequery
 
         self._prefetch_map = {}  # type: Dict[str, Set[str]]
         self._prefetch_queries = {}  # type: Dict[str, QuerySet]