feat: Remove immediate persistence in delete operation

- Enhance delete implementation in JsonKVStorage by removing immediate persistence in delete operation
- Update documentation for drop method to clarify persistence behavior
- Add abstract delete method to BaseKVStorage

lightrag/base.py

@@ -123,6 +123,7 @@ class StorageNameSpace(ABC):
         3. Reset the storage to its initial state
         4. Handle cleanup of any resources
         5. Notify other processes if necessary
+        6. This action should persistent the data to disk immediately.
         
         Returns:
             dict[str, str]: Operation status and message with the following format:
@@ -207,6 +208,22 @@ class BaseKVStorage(StorageNameSpace, ABC):
     async def upsert(self, data: dict[str, dict[str, Any]]) -> None:
         """Upsert data"""
 
+    @abstractmethod
+    async def delete(self, ids: list[str]) -> None:
+        """Delete specific records from storage by their IDs
+        
+        This method will:
+        1. Remove the specified records from in-memory storage
+        2. For in-memory DB, update flags to notify other processes that data persistence is needed
+        3. For in-memory DB, changes will be persisted to disk during the next index_done_callback
+        
+        Args:
+            ids (list[str]): List of document IDs to be deleted from storage
+        
+        Returns:
+            None
+        """
+
 
 @dataclass
 class BaseGraphStorage(StorageNameSpace, ABC):

lightrag/kg/json_kv_impl.py

@@ -122,14 +122,27 @@ class JsonKVStorage(BaseKVStorage):
             await set_all_update_flags(self.namespace)
 
     async def delete(self, ids: list[str]) -> None:
+        """Delete specific records from storage by their IDs
+        
+        This method will:
+        1. Remove the specified records from in-memory storage
+        2. Update flags to notify other processes that data persistence is needed
+        3. The changes will be persisted to disk during the next index_done_callback
+        
+        Args:
+            ids (list[str]): List of document IDs to be deleted from storage
+        
+        Returns:
+            None
+        """
         async with self._storage_lock:
             for doc_id in ids:
                 self._data.pop(doc_id, None)
             await set_all_update_flags(self.namespace)
-        await self.index_done_callback()
 
     async def drop(self) -> dict[str, str]:
         """Drop all data from storage and clean up resources
+           This action will persistent the data to disk immediately.
         
         This method will:
         1. Clear all data from memory