diff --git a/ptvp35/__init__.py b/ptvp35/__init__.py
index eccacbe..767ab41 100644
--- a/ptvp35/__init__.py
+++ b/ptvp35/__init__.py
@@ -102,7 +102,6 @@ class TransactionRequest(Request):
 class DbConnection:
     __mmdb: dict
     __loop: asyncio.AbstractEventLoop
-    __pool: concurrent.futures.Executor
     __queue: asyncio.Queue[Request]
     __file: IO[str]
     __buffer: StringIO
@@ -181,7 +180,7 @@ class DbConnection:
 
     async def _dump_compressed_buffer(self):
         buffer = self._compress_buffer()
-        await self.__loop.run_in_executor(self.__pool, self.__file.write, buffer.getvalue())
+        await self.__loop.run_in_executor(None, self.__file.write, buffer.getvalue())
 
     async def _do_dump_buffer(self):
         await self._dump_compressed_buffer()
@@ -198,7 +197,7 @@ class DbConnection:
 
     async def _save_error(self, line: str):
         with open(self.__path_error, 'a') as file:
-            await self.__loop.run_in_executor(self.__pool, file.write, line.strip() + '\n')
+            await self.__loop.run_in_executor(None, file.write, line.strip() + '\n')
 
     async def _handle_request(self, request: Request):
         if isinstance(request, self.factory.kvrequest_type):
@@ -227,13 +226,14 @@ class DbConnection:
             await self._background_cycle()
 
     async def _finish_recovery(self):
-        await self.__loop.run_in_executor(self.__pool, shutil.copy, self.__path_backup, self.__path)
+        with concurrent.futures.ThreadPoolExecutor() as pool:
+            await self.__loop.run_in_executor(pool, shutil.copy, self.__path_backup, self.__path)
         self.__path_recover.unlink()
         self.__path_backup.unlink()
 
     async def _build_file(self, db: dict):
-        with open(self.__path_backup, "w") as file:
-            self.__initial_size = await self.__loop.run_in_executor(self.__pool, self.db2io, db, file)
+        with open(self.__path_backup, "w") as file, concurrent.futures.ThreadPoolExecutor() as pool:
+            self.__initial_size = await self.__loop.run_in_executor(pool, self.db2io, db, file)
         self.__path_recover.touch()
         await self._finish_recovery()
 
@@ -242,7 +242,7 @@ class DbConnection:
             await self._finish_recovery()
         self.__path.touch()
         with open(self.__path) as file:
-            await self.__loop.run_in_executor(self.__pool, self.io2db, file, db)
+            await self.__loop.run_in_executor(None, self.io2db, file, db)
         await self._build_file(db)
 
     async def _reload(self):
@@ -268,7 +268,6 @@ class DbConnection:
     async def _initialize(self):
         assert self.not_running
         self.__loop = asyncio.get_event_loop()
-        self.__pool = concurrent.futures.ThreadPoolExecutor()
         await self._initialize_queue()
         await self._initialize_mmdb()
         await self._start_task()
@@ -286,14 +285,10 @@ class DbConnection:
             self.__task.cancel()
         await self._dump_buffer()
         self.__file.close()
-        self.__pool.shutdown()
-        self.__pool = concurrent.futures.ThreadPoolExecutor()
         await self._build_file(self.__mmdb)
         self.not_running = True
-        self.__pool.shutdown()
         del self.__mmdb
         del self.__loop
-        del self.__pool
         del self.__queue
         del self.__file
         del self.__buffer