diff --git a/.gitmodules b/.gitmodules
index 6e6d3f0..21367a0 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "third_party/benchmark"]
 	path = third_party/benchmark
 	url = https://github.com/google/benchmark
+[submodule "YCSB-cpp"]
+	path = YCSB-cpp
+	url = https://github.com/ls4154/YCSB-cpp.git
diff --git a/YCSB-cpp b/YCSB-cpp
new file mode 160000
index 0000000..b8e5cc1
--- /dev/null
+++ b/YCSB-cpp
@@ -0,0 +1 @@
+Subproject commit b8e5cc1446a3df02f09d045b045434bdebf27405
diff --git a/db/version_set.cc b/db/version_set.cc
index b362920..2128186 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -984,7 +984,7 @@ Status VersionSet::Recover(bool* save_manifest) {
   for (const auto& filename:filenames) {
     if (IsValueLogFile(filename)){
       uint64_t valuelog_number = GetValueLogID(filename);
-      std::cout<<valuelog_number<<std::endl;
+      //std::cout<<valuelog_number<<std::endl;
       MarkFileNumberUsed(valuelog_number);
     }
   }