diff --git a/cpp/src/server/RocksIdMapper.cpp b/cpp/src/server/RocksIdMapper.cpp
index 1f24f6c9da254d009cf521d6a7b9c628fd779416..386058f00e8ca24d72b0d02c942379b241be5ce2 100644
--- a/cpp/src/server/RocksIdMapper.cpp
+++ b/cpp/src/server/RocksIdMapper.cpp
@@ -30,6 +30,8 @@ RocksIdMapper::~RocksIdMapper() {
 }
 
 void RocksIdMapper::OpenDb() {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
     if(db_) {
         return;
     }
@@ -81,6 +83,8 @@ void RocksIdMapper::OpenDb() {
 }
 
 void RocksIdMapper::CloseDb() {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
     for(auto& iter : column_handles_) {
         delete iter.second;
     }
@@ -92,9 +96,86 @@ void RocksIdMapper::CloseDb() {
     }
 }
 
-//not thread-safe
 ServerError RocksIdMapper::AddGroup(const std::string& group) {
-    if(!IsGroupExist(group)) {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    return AddGroupInternal(group);
+}
+
+bool RocksIdMapper::IsGroupExist(const std::string& group) const {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    return IsGroupExistInternal(group);
+}
+
+
+ServerError RocksIdMapper::Put(const std::string& nid, const std::string& sid, const std::string& group) {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    return PutInternal(nid, sid, group);
+}
+
+ServerError RocksIdMapper::Put(const std::vector<std::string>& nid, const std::vector<std::string>& sid, const std::string& group) {
+    if(nid.size() != sid.size()) {
+        return SERVER_INVALID_ARGUMENT;
+    }
+
+    std::lock_guard<std::mutex> lck(db_mutex_);
+    ServerError err = SERVER_SUCCESS;
+    for(size_t i = 0; i < nid.size(); i++) {
+        err = PutInternal(nid[i], sid[i], group);
+        if(err != SERVER_SUCCESS) {
+            return err;
+        }
+    }
+
+    return err;
+}
+
+ServerError RocksIdMapper::Get(const std::string& nid, std::string& sid, const std::string& group) const {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    return GetInternal(nid, sid, group);
+}
+
+ServerError RocksIdMapper::Get(const std::vector<std::string>& nid, std::vector<std::string>& sid, const std::string& group) const {
+    sid.clear();
+
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    ServerError err = SERVER_SUCCESS;
+    for(size_t i = 0; i < nid.size(); i++) {
+        std::string str_id;
+        ServerError temp_err = GetInternal(nid[i], str_id, group);
+        if(temp_err != SERVER_SUCCESS) {
+            sid.push_back("");
+            SERVER_LOG_ERROR << "ID mapper failed to get id: " << nid[i];
+            err = temp_err;
+            continue;
+        }
+
+        sid.push_back(str_id);
+    }
+
+    return err;
+}
+
+ServerError RocksIdMapper::Delete(const std::string& nid, const std::string& group) {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    return DeleteInternal(nid, group);
+}
+
+ServerError RocksIdMapper::DeleteGroup(const std::string& group) {
+    std::lock_guard<std::mutex> lck(db_mutex_);
+
+    return DeleteGroupInternal(group);
+}
+
+//internal methods(whitout lock)
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+ServerError RocksIdMapper::AddGroupInternal(const std::string& group) {
+    if(!IsGroupExistInternal(group)) {
         if(db_ == nullptr) {
             return SERVER_NULL_POINTER;
         }
@@ -117,8 +198,7 @@ ServerError RocksIdMapper::AddGroup(const std::string& group) {
     return SERVER_SUCCESS;
 }
 
-//not thread-safe
-bool RocksIdMapper::IsGroupExist(const std::string& group) const {
+bool RocksIdMapper::IsGroupExistInternal(const std::string& group) const {
     std::string group_name = group;
     if(group_name.empty()){
         group_name = ROCKSDB_DEFAULT_GROUP;
@@ -126,7 +206,7 @@ bool RocksIdMapper::IsGroupExist(const std::string& group) const {
     return (column_handles_.count(group_name) > 0 && column_handles_[group_name] != nullptr);
 }
 
-ServerError RocksIdMapper::Put(const std::string& nid, const std::string& sid, const std::string& group) {
+ServerError RocksIdMapper::PutInternal(const std::string& nid, const std::string& sid, const std::string& group) {
     if(db_ == nullptr) {
         return SERVER_NULL_POINTER;
     }
@@ -141,7 +221,7 @@ ServerError RocksIdMapper::Put(const std::string& nid, const std::string& sid, c
         }
     } else {
         //try create group
-        if(AddGroup(group) != SERVER_SUCCESS){
+        if(AddGroupInternal(group) != SERVER_SUCCESS){
             return SERVER_UNEXPECTED_ERROR;
         }
 
@@ -156,23 +236,7 @@ ServerError RocksIdMapper::Put(const std::string& nid, const std::string& sid, c
     return SERVER_SUCCESS;
 }
 
-ServerError RocksIdMapper::Put(const std::vector<std::string>& nid, const std::vector<std::string>& sid, const std::string& group) {
-    if(nid.size() != sid.size()) {
-        return SERVER_INVALID_ARGUMENT;
-    }
-
-    ServerError err = SERVER_SUCCESS;
-    for(size_t i = 0; i < nid.size(); i++) {
-        err = Put(nid[i], sid[i], group);
-        if(err != SERVER_SUCCESS) {
-            return err;
-        }
-    }
-
-    return err;
-}
-
-ServerError RocksIdMapper::Get(const std::string& nid, std::string& sid, const std::string& group) const {
+ServerError RocksIdMapper::GetInternal(const std::string& nid, std::string& sid, const std::string& group) const {
     sid = "";
     if(db_ == nullptr) {
         return SERVER_NULL_POINTER;
@@ -199,28 +263,8 @@ ServerError RocksIdMapper::Get(const std::string& nid, std::string& sid, const s
     return SERVER_SUCCESS;
 }
 
-ServerError RocksIdMapper::Get(const std::vector<std::string>& nid, std::vector<std::string>& sid, const std::string& group) const {
-    sid.clear();
-
-    ServerError err = SERVER_SUCCESS;
-    for(size_t i = 0; i < nid.size(); i++) {
-        std::string str_id;
-        ServerError temp_err = Get(nid[i], str_id, group);
-        if(temp_err != SERVER_SUCCESS) {
-            sid.push_back("");
-            SERVER_LOG_ERROR << "ID mapper failed to get id: " << nid[i];
-            err = temp_err;
-            continue;
-        }
-
-        sid.push_back(str_id);
-    }
-
-    return err;
-}
-
-ServerError RocksIdMapper::Delete(const std::string& nid, const std::string& group) {
-    if(db_ == nullptr) {
+ServerError RocksIdMapper::DeleteInternal(const std::string& nid, const std::string& group) {
+     if(db_ == nullptr) {
         return SERVER_NULL_POINTER;
     }
 
@@ -244,7 +288,7 @@ ServerError RocksIdMapper::Delete(const std::string& nid, const std::string& gro
     return SERVER_SUCCESS;
 }
 
-ServerError RocksIdMapper::DeleteGroup(const std::string& group) {
+ServerError RocksIdMapper::DeleteGroupInternal(const std::string& group) {
     if(db_ == nullptr) {
         return SERVER_NULL_POINTER;
     }
diff --git a/cpp/src/server/RocksIdMapper.h b/cpp/src/server/RocksIdMapper.h
index 70b77eee04b1986726af2277982fc64f5c97a5df..5fc4667e75875866dd06d8bfad3d823628d2f9ed 100644
--- a/cpp/src/server/RocksIdMapper.h
+++ b/cpp/src/server/RocksIdMapper.h
@@ -13,6 +13,7 @@
 #include <string>
 #include <vector>
 #include <unordered_map>
+#include <mutex>
 
 namespace zilliz {
 namespace vecwise {
@@ -39,9 +40,22 @@ private:
     void OpenDb();
     void CloseDb();
 
+    ServerError AddGroupInternal(const std::string& group);
+
+    bool IsGroupExistInternal(const std::string& group) const;
+
+    ServerError PutInternal(const std::string& nid, const std::string& sid, const std::string& group);
+
+    ServerError GetInternal(const std::string& nid, std::string& sid, const std::string& group) const;
+
+    ServerError DeleteInternal(const std::string& nid, const std::string& group);
+
+    ServerError DeleteGroupInternal(const std::string& group);
+
 private:
     rocksdb::DB* db_;
     mutable std::unordered_map<std::string, rocksdb::ColumnFamilyHandle*> column_handles_;
+    mutable std::mutex db_mutex_;
 };
 
 }