diff --git a/lightrag/kg/json_kv_impl.py b/lightrag/kg/json_kv_impl.py
index 70a60aa2..59da1b54 100644
--- a/lightrag/kg/json_kv_impl.py
+++ b/lightrag/kg/json_kv_impl.py
@@ -28,10 +28,10 @@ class JsonKVStorage(BaseKVStorage):
     async def index_done_callback(self):
         write_json(self._data, self._file_name)
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
-        return self._data.get(id, None)
+    async def get_by_id(self, id: str) -> dict[str, Any]:
+        return self._data.get(id, {})
 
-    async def get_by_ids(self, ids: list[str]) -> list[Union[dict[str, Any], None]]:
+    async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
         return [
             (
                 {k: v for k, v in self._data[id].items()}
@@ -51,7 +51,7 @@ class JsonKVStorage(BaseKVStorage):
     async def drop(self) -> None:
         self._data = {}
 
-    async def get_by_status_and_ids(
+    async def get_by_status(
         self, status: str
     ) -> Union[list[dict[str, Any]], None]:
         result = [v for _, v in self._data.items() if v["status"] == status]
diff --git a/lightrag/kg/jsondocstatus_impl.py b/lightrag/kg/jsondocstatus_impl.py
index 8bd972c6..603487bc 100644
--- a/lightrag/kg/jsondocstatus_impl.py
+++ b/lightrag/kg/jsondocstatus_impl.py
@@ -72,7 +72,7 @@ class JsonDocStatusStorage(DocStatusStorage):
     def __post_init__(self):
         working_dir = self.global_config["working_dir"]
         self._file_name = os.path.join(working_dir, f"kv_store_{self.namespace}.json")
-        self._data = load_json(self._file_name) or {}
+        self._data: dict[str, Any] = load_json(self._file_name) or {}
         logger.info(f"Loaded document status storage with {len(self._data)} records")
 
     async def filter_keys(self, data: list[str]) -> set[str]:
@@ -112,10 +112,9 @@ class JsonDocStatusStorage(DocStatusStorage):
         """
         self._data.update(data)
         await self.index_done_callback()
-        return data
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
-        return self._data.get(id)
+    async def get_by_id(self, id: str) -> dict[str, Any]:
+        return self._data.get(id, {})
 
     async def get(self, doc_id: str) -> Union[DocProcessingStatus, None]:
         """Get document status by ID"""
diff --git a/lightrag/kg/mongo_impl.py b/lightrag/kg/mongo_impl.py
index ce703dfb..eb896b63 100644
--- a/lightrag/kg/mongo_impl.py
+++ b/lightrag/kg/mongo_impl.py
@@ -32,10 +32,10 @@ class MongoKVStorage(BaseKVStorage):
     async def all_keys(self) -> list[str]:
         return [x["_id"] for x in self._data.find({}, {"_id": 1})]
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
+    async def get_by_id(self, id: str) -> dict[str, Any]:
         return self._data.find_one({"_id": id})
 
-    async def get_by_ids(self, ids: list[str]) -> list[Union[dict[str, Any], None]]:
+    async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
         return list(self._data.find({"_id": {"$in": ids}}))
 
     async def filter_keys(self, data: list[str]) -> set[str]:
@@ -77,7 +77,7 @@ class MongoKVStorage(BaseKVStorage):
         """Drop the collection"""
         await self._data.drop()
 
-    async def get_by_status_and_ids(
+    async def get_by_status(
         self, status: str
     ) -> Union[list[dict[str, Any]], None]:
         """Get documents by status and ids"""
diff --git a/lightrag/kg/oracle_impl.py b/lightrag/kg/oracle_impl.py
index 3c064eba..0e55194d 100644
--- a/lightrag/kg/oracle_impl.py
+++ b/lightrag/kg/oracle_impl.py
@@ -181,7 +181,7 @@ class OracleKVStorage(BaseKVStorage):
 
     ################ QUERY METHODS ################
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
+    async def get_by_id(self, id: str) -> dict[str, Any]:
         """get doc_full data based on id."""
         SQL = SQL_TEMPLATES["get_by_id_" + self.namespace]
         params = {"workspace": self.db.workspace, "id": id}
@@ -191,12 +191,9 @@ class OracleKVStorage(BaseKVStorage):
             res = {}
             for row in array_res:
                 res[row["id"]] = row
-        else:
-            res = await self.db.query(SQL, params)
-        if res:
             return res
         else:
-            return None
+            return await self.db.query(SQL, params)
 
     async def get_by_mode_and_id(self, mode: str, id: str) -> Union[dict, None]:
         """Specifically for llm_response_cache."""
@@ -211,7 +208,7 @@ class OracleKVStorage(BaseKVStorage):
         else:
             return None
 
-    async def get_by_ids(self, ids: list[str]) -> list[Union[dict[str, Any], None]]:
+    async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
         """get doc_chunks data based on id"""
         SQL = SQL_TEMPLATES["get_by_ids_" + self.namespace].format(
             ids=",".join([f"'{id}'" for id in ids])
@@ -230,14 +227,9 @@ class OracleKVStorage(BaseKVStorage):
             for row in res:
                 dict_res[row["mode"]][row["id"]] = row
             res = [{k: v} for k, v in dict_res.items()]
-        if res:
-            data = res  # [{"data":i} for i in res]
-            # print(data)
-            return data
-        else:
-            return None
+        return res
 
-    async def get_by_status_and_ids(
+    async def get_by_status(
         self, status: str
     ) -> Union[list[dict[str, Any]], None]:
         """Specifically for llm_response_cache."""
diff --git a/lightrag/kg/postgres_impl.py b/lightrag/kg/postgres_impl.py
index ba11fea7..d966fd85 100644
--- a/lightrag/kg/postgres_impl.py
+++ b/lightrag/kg/postgres_impl.py
@@ -183,7 +183,7 @@ class PGKVStorage(BaseKVStorage):
 
     ################ QUERY METHODS ################
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
+    async def get_by_id(self, id: str) -> dict[str, Any]:
         """Get doc_full data by id."""
         sql = SQL_TEMPLATES["get_by_id_" + self.namespace]
         params = {"workspace": self.db.workspace, "id": id}
@@ -192,12 +192,9 @@ class PGKVStorage(BaseKVStorage):
             res = {}
             for row in array_res:
                 res[row["id"]] = row
-        else:
-            res = await self.db.query(sql, params)
-        if res:
             return res
         else:
-            return None
+            return await self.db.query(sql, params)
 
     async def get_by_mode_and_id(self, mode: str, id: str) -> Union[dict, None]:
         """Specifically for llm_response_cache."""
@@ -213,7 +210,7 @@ class PGKVStorage(BaseKVStorage):
             return None
 
     # Query by id
-    async def get_by_ids(self, ids: list[str]) -> list[Union[dict[str, Any], None]]:
+    async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
         """Get doc_chunks data by id"""
         sql = SQL_TEMPLATES["get_by_ids_" + self.namespace].format(
             ids=",".join([f"'{id}'" for id in ids])
@@ -230,15 +227,11 @@ class PGKVStorage(BaseKVStorage):
                     dict_res[mode] = {}
             for row in array_res:
                 dict_res[row["mode"]][row["id"]] = row
-            res = [{k: v} for k, v in dict_res.items()]
+            return [{k: v} for k, v in dict_res.items()]
         else:
-            res = await self.db.query(sql, params, multirows=True)
-        if res:
-            return res
-        else:
-            return None
+            return await self.db.query(sql, params, multirows=True)
 
-    async def get_by_status_and_ids(
+    async def get_by_status(
         self, status: str
     ) -> Union[list[dict[str, Any]], None]:
         """Specifically for llm_response_cache."""
@@ -454,12 +447,12 @@ class PGDocStatusStorage(DocStatusStorage):
             existed = set([element["id"] for element in result])
             return set(data) - existed
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
+    async def get_by_id(self, id: str) -> dict[str, Any]:
         sql = "select * from LIGHTRAG_DOC_STATUS where workspace=$1 and id=$2"
         params = {"workspace": self.db.workspace, "id": id}
         result = await self.db.query(sql, params, True)
         if result is None or result == []:
-            return None
+            return {}
         else:
             return DocProcessingStatus(
                 content_length=result[0]["content_length"],
diff --git a/lightrag/kg/redis_impl.py b/lightrag/kg/redis_impl.py
index 095cc3b6..7c5c7030 100644
--- a/lightrag/kg/redis_impl.py
+++ b/lightrag/kg/redis_impl.py
@@ -29,7 +29,7 @@ class RedisKVStorage(BaseKVStorage):
         data = await self._redis.get(f"{self.namespace}:{id}")
         return json.loads(data) if data else None
 
-    async def get_by_ids(self, ids: list[str]) -> list[Union[dict[str, Any], None]]:
+    async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
         pipe = self._redis.pipeline()
         for id in ids:
             pipe.get(f"{self.namespace}:{id}")
@@ -59,7 +59,7 @@ class RedisKVStorage(BaseKVStorage):
         if keys:
             await self._redis.delete(*keys)
 
-    async def get_by_status_and_ids(
+    async def get_by_status(
         self, status: str
     ) -> Union[list[dict[str, Any]], None]:
         pipe = self._redis.pipeline()
diff --git a/lightrag/kg/tidb_impl.py b/lightrag/kg/tidb_impl.py
index b8e6e985..55dbe303 100644
--- a/lightrag/kg/tidb_impl.py
+++ b/lightrag/kg/tidb_impl.py
@@ -108,31 +108,20 @@ class TiDBKVStorage(BaseKVStorage):
 
     ################ QUERY METHODS ################
 
-    async def get_by_id(self, id: str) -> Union[dict[str, Any], None]:
-        """根据 id 获取 doc_full 数据."""
+    async def get_by_id(self, id: str) -> dict[str, Any]:
+        """Fetch doc_full data by id."""
         SQL = SQL_TEMPLATES["get_by_id_" + self.namespace]
         params = {"id": id}
         # print("get_by_id:"+SQL)
-        res = await self.db.query(SQL, params)
-        if res:
-            data = res  # {"data":res}
-            # print (data)
-            return data
-        else:
-            return None
+        return await self.db.query(SQL, params)
 
     # Query by id
-    async def get_by_ids(self, ids: list[str]) -> list[Union[dict[str, Any], None]]:
-        """根据 id 获取 doc_chunks 数据"""
+    async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
+        """Fetch doc_chunks data by id"""
         SQL = SQL_TEMPLATES["get_by_ids_" + self.namespace].format(
             ids=",".join([f"'{id}'" for id in ids])
         )
-        res = await self.db.query(SQL, multirows=True)
-        if res:
-            data = res  # [{"data":i} for i in res]
-            return data
-        else:
-            return None
+        return await self.db.query(SQL, multirows=True)
 
     async def filter_keys(self, keys: list[str]) -> set[str]:
         """过滤掉重复内容"""
@@ -333,7 +322,7 @@ class TiDBVectorDBStorage(BaseVectorStorage):
                 merge_sql = SQL_TEMPLATES["insert_relationship"]
                 await self.db.execute(merge_sql, data)
 
-    async def get_by_status_and_ids(
+    async def get_by_status(
         self, status: str
     ) -> Union[list[dict[str, Any]], None]:
         SQL = SQL_TEMPLATES["get_by_status_" + self.namespace]