diff --git a/backend/app/models/chunk.py b/backend/app/models/chunk.py
index c762da3cb..8e000e30c 100644
--- a/backend/app/models/chunk.py
+++ b/backend/app/models/chunk.py
@@ -1,6 +1,7 @@
 import enum
 from functools import lru_cache
 
+import sys
 from typing import Optional, Type
 from sqlmodel import (
     Field,
@@ -34,7 +35,7 @@ def get_kb_chunk_model(kb: KnowledgeBase) -> Type[SQLModel]:
     return get_dynamic_chunk_model(vector_dimension, str(kb.id))
 
 
-@lru_cache(maxsize=None)
+@lru_cache(maxsize=sys.maxsize)
 def get_dynamic_chunk_model(
     vector_dimension: int,
     namespace: Optional[str] = None,
diff --git a/backend/app/models/entity.py b/backend/app/models/entity.py
index a2d401d16..64fa006e8 100644
--- a/backend/app/models/entity.py
+++ b/backend/app/models/entity.py
@@ -1,5 +1,6 @@
 import enum
 from functools import lru_cache
+import sys
 from typing import Optional, List, Dict, Type
 
 from sqlmodel import (
@@ -40,7 +41,7 @@ def get_kb_entity_model(kb: KnowledgeBase) -> Type[SQLModel]:
     return get_dynamic_entity_model(vector_dimension, str(kb.id))
 
 
-@lru_cache(maxsize=None)
+@lru_cache(maxsize=sys.maxsize)
 def get_dynamic_entity_model(
     vector_dimension: int,
     namespace: Optional[str] = None,
diff --git a/backend/app/models/relationship.py b/backend/app/models/relationship.py
index 531c73b59..452cd925d 100644
--- a/backend/app/models/relationship.py
+++ b/backend/app/models/relationship.py
@@ -1,5 +1,6 @@
 from datetime import datetime
 from functools import lru_cache
+import sys
 from typing import Optional, Type
 from uuid import UUID
 
@@ -36,7 +37,7 @@ def get_kb_relationship_model(kb: KnowledgeBase) -> Type[SQLModel]:
     return get_dynamic_relationship_model(vector_dimension, str(kb.id), entity_model)
 
 
-@lru_cache(maxsize=None)
+@lru_cache(maxsize=sys.maxsize)
 def get_dynamic_relationship_model(
     vector_dimension: int,
     namespace: Optional[str] = None,