diff --git a/src/memos/memories/textual/tree_text_memory/retrieve/searcher.py b/src/memos/memories/textual/tree_text_memory/retrieve/searcher.py
index f3d6ba03..7e28c174 100644
--- a/src/memos/memories/textual/tree_text_memory/retrieve/searcher.py
+++ b/src/memos/memories/textual/tree_text_memory/retrieve/searcher.py
@@ -674,6 +674,8 @@ def _retrieve_simple(
         )
         logger.info(f"[SIMPLESEARCH] Items count: {len(items)}")
         documents = [getattr(item, "memory", "") for item in items]
+        if not documents:
+            return []
         documents_embeddings = self.embedder.embed(documents)
         similarity_matrix = cosine_similarity_matrix(documents_embeddings)
         selected_indices, _ = find_best_unrelated_subgroup(documents, similarity_matrix)
diff --git a/src/memos/multi_mem_cube/composite_cube.py b/src/memos/multi_mem_cube/composite_cube.py
index 42085640..c1017bfa 100644
--- a/src/memos/multi_mem_cube/composite_cube.py
+++ b/src/memos/multi_mem_cube/composite_cube.py
@@ -1,9 +1,10 @@
 from __future__ import annotations
 
-from concurrent.futures import ThreadPoolExecutor, as_completed
+from concurrent.futures import as_completed
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any
 
+from memos.context.context import ContextThreadPoolExecutor
 from memos.multi_mem_cube.views import MemCubeView
 
 
@@ -52,7 +53,7 @@ def _search_single_cube(view: SingleCubeView) -> dict[str, Any]:
             return view.search_memories(search_req)
 
         # parallel search for each cube
-        with ThreadPoolExecutor(max_workers=2) as executor:
+        with ContextThreadPoolExecutor(max_workers=2) as executor:
             future_to_view = {
                 executor.submit(_search_single_cube, view): view for view in self.cube_views
             }