perf: renaming a folder or deleting all chats takes seconds when many users are online (#32888)

* perf: renaming a folder or deleting all chats takes seconds when many users are online

Renaming, sharing, moving or deleting a folder, and deleting all chats, each made the server recheck access for every chat that any online user had open in a browser tab, one database lookup at a time, before the request finished, and every one of those open chats reloaded its contents afterwards. Any user can do these, so with a few thousand people online every such click took several seconds and reloaded everyone's open chat. Owners keep access to their own chats (a role change or account deletion already disconnects them), so the recheck now skips owners entirely, with no lookup and no reload, and only checks people viewing someone else's chat and chats that no longer exist. Anyone who lost access is still removed from the chat as before.

Postgres 16, one open chat per online user, 2% of them viewing someone else's chat, time for a folder rename (the other actions above run the same recheck):

| Online users | No Redis, before | No Redis, after | Redis, before | Redis, after |
| --- | --- | --- | --- | --- |
| 1,000 | 2.2 s | 0.12 s | 2.5 s | 0.23 s |
| 3,000 | 6.9 s | 0.60 s | 7.7 s | 0.78 s |

* refac: collect the open chats with a plain loop

Same behaviour, the owner lookup now reads more plainly.

* refac: shorten the owner comment in the chat access sweep

backend/open_webui/models/chats.py

@@ -1793,6 +1793,13 @@ class ChatTable:
             result = await session.execute(stmt)
             return [meta for meta in result.scalars().all() if isinstance(meta, dict)]
 
+    async def get_owner_ids_by_chat_ids(self, chat_ids: list[str], db: AsyncSession | None = None) -> dict[str, str]:
+        if not chat_ids:
+            return {}
+        async with get_async_db_context(db) as session:
+            result = await session.execute(select(Chat.id, Chat.user_id).filter(Chat.id.in_(chat_ids)))
+            return dict(result.all())
+
     async def get_chats_by_model_id(
         self,
         model_id: str,

backend/open_webui/socket/main.py

@@ -622,12 +622,23 @@ async def refresh_chat_access(chat_id=None):
     access = {}
     chat_ids = set()
     for batch in get_session_pool_batches():
+        chat_owner_ids: dict[str, str] = {}
+        if not chat_id:
+            # Owners keep access; role changes and deletion disconnect them separately.
+            open_chat_ids: set[str] = set()
+            for _, session in batch:
+                if not session:
+                    continue
+                open_chat_ids.update(session.get('chat_ids') or [])
+            chat_owner_ids = await Chats.get_owner_ids_by_chat_ids(list(open_chat_ids))
         for sid, session in batch:
             if not session:
                 continue
             for cid in session.get('chat_ids') or []:
                 if chat_id and cid != chat_id:
                     continue
+                if chat_owner_ids.get(cid) == session['id']:
+                    continue
                 key = (cid, session['id'])
                 if key not in access:
                     user = await Users.get_user_by_id(session['id'])