Update utils.py

Avoid running any tasks for collections that failed to fetch data (have assigned None)

backend/open_webui/retrieval/utils.py

@@ -320,11 +320,9 @@ def query_collection_with_hybrid_search(
             log.exception(f"Error when querying the collection with hybrid_search: {e}")
             return None, e
 
-    tasks = [
-        (collection_name, query)
-        for collection_name in collection_names
-        for query in queries
-    ]
+    # Prepare tasks for all collections and queries
+    # Avoid running any tasks for collections that failed to fetch data (have assigned None)
+    tasks = [(cn, q) for cn in collection_names if collection_results[cn] is not None for q in queries]
 
     with ThreadPoolExecutor() as executor:
         future_results = [executor.submit(process_query, cn, q) for cn, q in tasks]