perf: increase MAX_OVERFLOW of database connection pool.

apps/smartdoc/conf.py

@@ -111,7 +111,7 @@ def get_db_setting(self) -> dict:
             "ENGINE": self.get('DB_ENGINE'),
             "POOL_OPTIONS": {
                 "POOL_SIZE": 20,
-                "MAX_OVERFLOW": 5
+                "MAX_OVERFLOW": 80
             }
         }