From 7eaecbad5a0913ed04ca3bc10c930bb051dd2bd9 Mon Sep 17 00:00:00 2001
From: Timothy Jaeryang Baek <tim@openwebui.com>
Date: Sat, 9 May 2026 02:38:08 +0900
Subject: [PATCH] refac

---
 backend/open_webui/__init__.py    | 7 +++++++
 backend/open_webui/internal/db.py | 9 +++++++++
 2 files changed, 16 insertions(+)

diff --git a/backend/open_webui/__init__.py b/backend/open_webui/__init__.py
index be25227d36..92cadefe7c 100644
--- a/backend/open_webui/__init__.py
+++ b/backend/open_webui/__init__.py
@@ -1,6 +1,7 @@
 import base64
 import os
 import random
+import sys
 from pathlib import Path
 from typing import Annotated
 
@@ -68,12 +69,18 @@ def serve(
     import open_webui.main  # noqa: F401
     from open_webui.env import UVICORN_WORKERS  # Import the workers setting
 
+    # On Windows, uvicorn's default loop factory hardcodes ProactorEventLoop,
+    # which is incompatible with psycopg v3 async.  Setting loop='none' lets
+    # asyncio.run() respect the WindowsSelectorEventLoopPolicy set in db.py.
+    loop = 'none' if sys.platform == 'win32' else 'auto'
+
     uvicorn.run(
         'open_webui.main:app',
         host=host,
         port=port,
         forwarded_allow_ips='*',
         workers=UVICORN_WORKERS,
+        loop=loop,
     )
 
 
diff --git a/backend/open_webui/internal/db.py b/backend/open_webui/internal/db.py
index c9e4f318e1..1bb9db5bb4 100644
--- a/backend/open_webui/internal/db.py
+++ b/backend/open_webui/internal/db.py
@@ -1,4 +1,5 @@
 import os
+import sys
 import json
 import logging
 from contextlib import asynccontextmanager, contextmanager
@@ -332,6 +333,14 @@ get_db = contextmanager(get_session)
 # all work without any stripping or translation.
 ASYNC_SQLALCHEMY_DATABASE_URL = _make_async_url(SQLALCHEMY_DATABASE_URL)
 
+# psycopg v3 cannot run in async mode under Windows' default
+# ProactorEventLoop — switch to SelectorEventLoop before creating
+# the async engine.  This runs at import time, which is early enough
+# to cover every entry point (workers, reload, direct invocations).
+if sys.platform == 'win32' and _is_postgres_url(DATABASE_URL):
+    import asyncio
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+
 if 'sqlite' in ASYNC_SQLALCHEMY_DATABASE_URL:
     # Generous default — async coroutines + no session sharing = high connection demand.
     _sqlite_pool_size = DATABASE_POOL_SIZE if isinstance(DATABASE_POOL_SIZE, int) and DATABASE_POOL_SIZE > 0 else 512