diff --git a/README.md b/README.md
index e76f3a6..fcf5af7 100644
--- a/README.md
+++ b/README.md
@@ -18,3 +18,4 @@ ctest
 - [x] add write-ahead wal
 - [x] add immutable MemTable
 - [ ] redesign the structure of SSTable (integrate Bloom filter bits and metadata into files)
+- [ ] flush periodically