diff --git a/cpp/CHANGELOG.md b/cpp/CHANGELOG.md
index 6ea83b167afb4f3b75a6be2b4126916588caf679..78def9905bc1d01fbf51ee2793294207f6891288 100644
--- a/cpp/CHANGELOG.md
+++ b/cpp/CHANGELOG.md
@@ -38,6 +38,7 @@ Please mark all change in change log and use the ticket from JIRA.
 - MS-390 - Update resource construct function
 - MS-391 - Add PushTaskToNeighbourHasExecutor action
 - MS-394 - Update scheduler unittest
+- MS-400 - Add timestamp record in task state change function
 
 ## New Feature
 - MS-343 - Implement ResourceMgr
diff --git a/cpp/src/scheduler/ResourceMgr.cpp b/cpp/src/scheduler/ResourceMgr.cpp
index 1c8e7607c36b148bc5d7d52884250b5f640a5904..44ebbfad44ae2679dabd074174426e2b21258057 100644
--- a/cpp/src/scheduler/ResourceMgr.cpp
+++ b/cpp/src/scheduler/ResourceMgr.cpp
@@ -93,6 +93,17 @@ ResourceMgr::Dump() {
     return str;
 }
 
+std::string
+ResourceMgr::DumpTaskTables() {
+    std::stringstream ss;
+    ss << ">>>>>>>>>>>>>>>ResourceMgr::DumpTaskTable<<<<<<<<<<<<<<<" << std::endl;
+    for (auto &resource : resources_) {
+        ss << resource->Dump() << std::endl;
+        ss << resource->task_table().Dump() << std::endl;
+    }
+    return ss.str();
+}
+
 void
 ResourceMgr::event_process() {
     while (running_) {
diff --git a/cpp/src/scheduler/ResourceMgr.h b/cpp/src/scheduler/ResourceMgr.h
index 5d273a4f3881bfb11167babad8842c43cead9627..c3f900b2db25792c17ff61be20d6cef04933ef17 100644
--- a/cpp/src/scheduler/ResourceMgr.h
+++ b/cpp/src/scheduler/ResourceMgr.h
@@ -70,6 +70,9 @@ public:
     std::string
     Dump();
 
+    std::string
+    DumpTaskTables();
+
 private:
     void
     event_process();
diff --git a/cpp/src/scheduler/TaskTable.cpp b/cpp/src/scheduler/TaskTable.cpp
index 7ef033c500510a13667bfbbd0d8e8a7cfe3ae5ba..fb3c317747b87f971b7407efc8d957f1cc90cfe8 100644
--- a/cpp/src/scheduler/TaskTable.cpp
+++ b/cpp/src/scheduler/TaskTable.cpp
@@ -8,12 +8,88 @@
 #include "event/TaskTableUpdatedEvent.h"
 #include <vector>
 #include <sstream>
+#include <ctime>
 
 
 namespace zilliz {
 namespace milvus {
 namespace engine {
 
+uint64_t
+get_now_timestamp() {
+    std::chrono::time_point<std::chrono::system_clock> now = std::chrono::system_clock::now();
+    auto duration = now.time_since_epoch();
+    auto millis = std::chrono::duration_cast<std::chrono::milliseconds>(duration).count();
+    return millis;
+}
+
+bool
+TaskTableItem::Load() {
+    std::unique_lock<std::mutex> lock(mutex);
+    if (state == TaskTableItemState::START) {
+        state = TaskTableItemState::LOADING;
+        lock.unlock();
+        timestamp.load = get_now_timestamp();
+        return true;
+    }
+    return false;
+}
+bool
+TaskTableItem::Loaded() {
+    std::unique_lock<std::mutex> lock(mutex);
+    if (state == TaskTableItemState::LOADING) {
+        state = TaskTableItemState::LOADED;
+        lock.unlock();
+        timestamp.loaded = get_now_timestamp();
+        return true;
+    }
+    return false;
+}
+bool
+TaskTableItem::Execute() {
+    std::unique_lock<std::mutex> lock(mutex);
+    if (state == TaskTableItemState::LOADED) {
+        state = TaskTableItemState::EXECUTING;
+        lock.unlock();
+        timestamp.execute = get_now_timestamp();
+        return true;
+    }
+    return false;
+}
+bool
+TaskTableItem::Executed() {
+    std::unique_lock<std::mutex> lock(mutex);
+    if (state == TaskTableItemState::EXECUTING) {
+        state = TaskTableItemState::EXECUTED;
+        lock.unlock();
+        timestamp.executed = get_now_timestamp();
+        return true;
+    }
+    return false;
+}
+bool
+TaskTableItem::Move() {
+    std::unique_lock<std::mutex> lock(mutex);
+    if (state == TaskTableItemState::LOADED) {
+        state = TaskTableItemState::MOVING;
+        lock.unlock();
+        timestamp.move = get_now_timestamp();
+        return true;
+    }
+    return false;
+}
+bool
+TaskTableItem::Moved() {
+    std::unique_lock<std::mutex> lock(mutex);
+    if (state == TaskTableItemState::MOVING) {
+        state = TaskTableItemState::MOVED;
+        lock.unlock();
+        timestamp.moved = get_now_timestamp();
+        return true;
+    }
+    return false;
+}
+
 
 void
 TaskTable::Put(TaskPtr task) {
@@ -59,78 +135,6 @@ TaskTable::Clear() {
 //        table_.erase(table_.begin(), iterator);
 }
 
-bool
-TaskTable::Move(uint64_t index) {
-    auto &task = table_[index];
-
-    std::lock_guard<std::mutex> lock(task->mutex);
-    if (task->state == TaskTableItemState::LOADED) {
-        task->state = TaskTableItemState::MOVING;
-        return true;
-    }
-    return false;
-}
-
-bool
-TaskTable::Moved(uint64_t index) {
-    auto &task = table_[index];
-
-    std::lock_guard<std::mutex> lock(task->mutex);
-    if (task->state == TaskTableItemState::MOVING) {
-        task->state = TaskTableItemState::MOVED;
-        return true;
-    }
-    return false;
-}
-
-bool
-TaskTable::Load(uint64_t index) {
-    auto &task = table_[index];
-
-    std::lock_guard<std::mutex> lock(task->mutex);
-    if (task->state == TaskTableItemState::START) {
-        task->state = TaskTableItemState::LOADING;
-        return true;
-    }
-    return false;
-}
-
-bool
-TaskTable::Loaded(uint64_t index) {
-    auto &task = table_[index];
-
-    std::lock_guard<std::mutex> lock(task->mutex);
-    if (task->state == TaskTableItemState::LOADING) {
-        task->state = TaskTableItemState::LOADED;
-        return true;
-    }
-    return false;
-}
-
-bool
-TaskTable::Execute(uint64_t index) {
-    auto &task = table_[index];
-
-    std::lock_guard<std::mutex> lock(task->mutex);
-    if (task->state == TaskTableItemState::LOADED) {
-        task->state = TaskTableItemState::EXECUTING;
-        return true;
-    }
-    return false;
-}
-
-bool
-TaskTable::Executed(uint64_t index) {
-    auto &task = table_[index];
-
-    std::lock_guard<std::mutex> lock(task->mutex);
-    if (task->state == TaskTableItemState::EXECUTING) {
-        task->state = TaskTableItemState::EXECUTED;
-        return true;
-    }
-    return false;
-}
-
 std::string
 ToString(TaskTableItemState state) {
     switch (state) {
@@ -146,12 +150,27 @@ ToString(TaskTableItemState state) {
     }
 }
 
+std::string
+ToString(const TaskTimestamp &timestamp) {
+    std::stringstream ss;
+    ss << "<start=" << timestamp.start;
+    ss << ", load=" << timestamp.load;
+    ss << ", loaded=" << timestamp.loaded;
+    ss << ", execute=" << timestamp.execute;
+    ss << ", executed=" << timestamp.executed;
+    ss << ", move=" << timestamp.move;
+    ss << ", moved=" << timestamp.moved;
+    ss << ">";
+    return ss.str();
+}
+
 std::string
 TaskTable::Dump() {
     std::stringstream ss;
     for (auto &item : table_) {
-        ss << "<" << item->id;
-        ss << ", " << ToString(item->state);
+        ss << "<id=" << item->id;
+        ss << ", state=" << ToString(item->state);
+        ss << ", timestamp=" << ToString(item->timestamp);
         ss << ">" << std::endl;
     }
     return ss.str();
diff --git a/cpp/src/scheduler/TaskTable.h b/cpp/src/scheduler/TaskTable.h
index 8a482d0579a386f2bbbc59ca59c7df3e581938e8..45cb9a815e05bd9ed5df0730f3121bbd28851232 100644
--- a/cpp/src/scheduler/TaskTable.h
+++ b/cpp/src/scheduler/TaskTable.h
@@ -28,6 +28,16 @@ enum class TaskTableItemState {
     MOVED, // moved, termination state
 };
 
+struct TaskTimestamp {
+    uint64_t start = 0;
+    uint64_t move = 0;
+    uint64_t moved = 0;
+    uint64_t load = 0;
+    uint64_t loaded = 0;
+    uint64_t execute = 0;
+    uint64_t executed = 0;
+};
+
 struct TaskTableItem {
     TaskTableItem() : id(0), state(TaskTableItemState::INVALID), mutex(), priority(0) {}
 
@@ -39,8 +49,27 @@ struct TaskTableItem {
     TaskPtr task; // the task;
     TaskTableItemState state; // the state;
     std::mutex mutex;
+    TaskTimestamp timestamp;
 
     uint8_t priority; // just a number, meaningless;
+
+    bool
+    Load();
+
+    bool
+    Loaded();
+
+    bool
+    Execute();
+
+    bool
+    Executed();
+
+    bool
+    Move();
+
+    bool
+    Moved();
 };
 
 using TaskTableItemPtr = std::shared_ptr<TaskTableItem>;
@@ -111,55 +140,68 @@ public:
 public:
 
     /******** Action ********/
-    /*
-     * Move a task;
-     * Set state moving;
-     * Called by scheduler;
-     */
 
     // TODO: bool to Status
-    bool
-    Move(uint64_t index);
-
-    /*
-     * Move task finished;
-     * Set state moved;
-     * Called by scheduler;
-     */
-    bool
-    Moved(uint64_t index);
-
     /*
      * Load a task;
      * Set state loading;
      * Called by loader;
      */
-    bool
-    Load(uint64_t index);
+    inline bool
+    Load(uint64_t index) {
+        return table_[index]->Load();
+    }
 
     /*
      * Load task finished;
      * Set state loaded;
      * Called by loader;
      */
-    bool
-    Loaded(uint64_t index);
+    inline bool
+    Loaded(uint64_t index) {
+        return table_[index]->Loaded();
+    }
 
     /*
      * Execute a task;
      * Set state executing;
      * Called by executor;
      */
-    bool
-    Execute(uint64_t index);
+    inline bool
+    Execute(uint64_t index) {
+        return table_[index]->Execute();
+    }
 
     /*
      * Execute task finished;
      * Set state executed;
      * Called by executor;
      */
-    bool
-    Executed(uint64_t index);
+    inline bool
+    Executed(uint64_t index){
+        return table_[index]->Executed();
+    }
+
+    /*
+     * Move a task;
+     * Set state moving;
+     * Called by scheduler;
+     */
+
+    inline bool
+    Move(uint64_t index){
+        return table_[index]->Move();
+    }
+
+    /*
+     * Move task finished;
+     * Set state moved;
+     * Called by scheduler;
+     */
+    inline bool
+    Moved(uint64_t index){
+        return table_[index]->Moved();
+    }
 
 public:
     /*
diff --git a/cpp/src/scheduler/resource/Resource.cpp b/cpp/src/scheduler/resource/Resource.cpp
index 0bb886fdf04cf5cd2b12fcb81452c33d5fc04779..77bcb28f3576269708430441ea91fe1495f011bc 100644
--- a/cpp/src/scheduler/resource/Resource.cpp
+++ b/cpp/src/scheduler/resource/Resource.cpp
@@ -112,7 +112,7 @@ void Resource::loader_function() {
             }
             LoadFile(task_item->task);
             // TODO: wrapper loaded
-            task_item->state = TaskTableItemState::LOADED;
+            task_item->Loaded();
             if (subscriber_) {
                 auto event = std::make_shared<CopyCompletedEvent>(shared_from_this(), task_item);
                 subscriber_(std::static_pointer_cast<Event>(event));
@@ -138,7 +138,7 @@ void Resource::executor_function() {
                 break;
             }
             Process(task_item->task);
-            task_item->state = TaskTableItemState::EXECUTED;
+            task_item->Executed();
             if (subscriber_) {
                 auto event = std::make_shared<FinishTaskEvent>(shared_from_this(), task_item);
                 subscriber_(std::static_pointer_cast<Event>(event));
diff --git a/cpp/src/scheduler/task/SearchTask.cpp b/cpp/src/scheduler/task/SearchTask.cpp
index 98cbdb219b3343657e04806f4e985d994d90b4cb..ea482bcb7210a4c9ffdcfb3c1d21678bdb085b93 100644
--- a/cpp/src/scheduler/task/SearchTask.cpp
+++ b/cpp/src/scheduler/task/SearchTask.cpp
@@ -113,7 +113,6 @@ XSearchTask::Load(LoadType type, uint8_t device_id) {
         if (type == LoadType::DISK2CPU) {
             index_engine_->Load();
         } else if (type == LoadType::CPU2GPU) {
-            index_engine_->Load();
             index_engine_->CopyToGpu(device_id);
         } else if (type == LoadType::GPU2CPU) {
             index_engine_->CopyToCpu();