Force task switch every 2000 rows when creating objects (#1939)

Author: henadzit

CHANGELOG.rst

@@ -9,6 +9,12 @@ Changelog
 0.25
 ====
 
+0.25.1 (unreleased)
+------------------
+Changed
+^^^^^
+- Force async task switch every 2000 rows when converting db objects to python objects to avoid blocking the event loop (#1939)
+
 0.25.0
 ------
 Fixed
@@ -24,10 +30,6 @@ Added
 ^^^^^
 - `.only` supports selecting related fields, e.g. `.only("related__field")` (#1923)
 
-Fixed
-^^^^^
-- Fix pydantic_model_creator incompatibility with Pydantic 2.11 (#1930)
-
 
 0.24
 ====

tortoise/backends/base/executor.py

@@ -32,6 +32,8 @@
     tuple[list, str, list, str, str, dict[str, str]],
 ] = {}
 
+CHUNK_SIZE = 2000
+
 
 class BaseExecutor:
     FILTER_FUNC_OVERRIDE: dict[Callable, Callable] = {}
@@ -105,7 +107,12 @@ async def execute_select(
     ) -> list:
         _, raw_results = await self.db.execute_query(sql, values)
         instance_list = []
-        for row in raw_results:
+        for row_idx, row in enumerate(raw_results):
+            if row_idx != 0 and row_idx % CHUNK_SIZE == 0:
+                # Forcibly yield to the event loop to avoid blocking the event loop
+                # when selecting a large number of rows
+                await asyncio.sleep(0)
+
             if self.select_related_idx:
                 _, current_idx, _, _, path = self.select_related_idx[0]
                 row_items = list(dict(row).items())