diff --git a/src/concurrency_control/bg_work/bg_commit.cpp b/src/concurrency_control/bg_work/bg_commit.cpp
index c4cf20f00..7795b7abd 100644
--- a/src/concurrency_control/bg_work/bg_commit.cpp
+++ b/src/concurrency_control/bg_work/bg_commit.cpp
@@ -72,6 +72,14 @@ void bg_commit::worker() {
     REFIND : // NOLINT
     {
         std::shared_lock<std::shared_mutex> lk1{mtx_cont_wait_tx()};
+        // if cont empty then clear used_ids
+        if (cont_wait_tx().empty()) {
+            {
+                std::unique_lock<std::mutex> lk2{mtx_used_ids()};
+                if (!used_ids().empty()) { used_ids().clear(); }
+            }
+            continue;
+        }
         auto itr = cont_wait_tx().begin();
         for (; itr != cont_wait_tx().end(); ++itr) {
             token = std::get<1>(*itr);
@@ -125,11 +133,6 @@ void bg_commit::worker() {
               * than this transaction wait for the result of this 
               * transaction.
               */
-            // erase from used_ids
-            {
-                std::unique_lock<std::mutex> lk2{mtx_used_ids()};
-                used_ids().erase(tx_id);
-            }
             goto REFIND; // NOLINT
         }                // termination was successed
         ti->set_result_requested_commit(rc);
@@ -138,11 +141,6 @@ void bg_commit::worker() {
         {
             std::lock_guard<std::shared_mutex> lk1{mtx_cont_wait_tx()};
             cont_wait_tx().erase(std::make_tuple(tx_id, token));
-            // erase from used_ids
-            {
-                std::unique_lock<std::mutex> lk2{mtx_used_ids()};
-                used_ids().erase(tx_id);
-            }
         }
 
         goto REFIND; // NOLINT
diff --git a/src/concurrency_control/include/tid.h b/src/concurrency_control/include/tid.h
index 9840416ba..b0dd01ea4 100644
--- a/src/concurrency_control/include/tid.h
+++ b/src/concurrency_control/include/tid.h
@@ -114,7 +114,7 @@ class tid_word { // NOLINT
 
     void display();
 
-    void lock(bool by_gc = false);
+    void lock(bool by_gc = false); // NOLINT
 
     /**
      * @pre This is called after lock() function.
diff --git a/src/concurrency_control/ongoing_tx.cpp b/src/concurrency_control/ongoing_tx.cpp
index 6b920cd1f..705d5858e 100644
--- a/src/concurrency_control/ongoing_tx.cpp
+++ b/src/concurrency_control/ongoing_tx.cpp
@@ -146,7 +146,6 @@ bool ongoing_tx::exist_wait_for(session* ti, Status& out_status) {
     std::size_t id = ti->get_long_tx_id();
     bool has_wp = !ti->get_wp_set().empty();
     auto wait_for = ti->extract_wait_for();
-    // TODO wait_for empty return false.
     // check local write set
     std::set<Storage> st_set{};
     // create and compaction about storage set
diff --git a/test/concurrency_control/long_tx/insert/long_insert_insert_conflict_diff_epoch_same_key_co_low_high_test.cpp b/test/concurrency_control/long_tx/insert/long_insert_insert_conflict_diff_epoch_same_key_co_low_high_test.cpp
index f18cd32bc..f5c9a0f88 100644
--- a/test/concurrency_control/long_tx/insert/long_insert_insert_conflict_diff_epoch_same_key_co_low_high_test.cpp
+++ b/test/concurrency_control/long_tx/insert/long_insert_insert_conflict_diff_epoch_same_key_co_low_high_test.cpp
@@ -85,6 +85,8 @@ TEST_F(long_insert_insert_conflict_diff_epoch_same_key_co_low_high_test, // NOLI
         _mm_pause();
     } while (rc == Status::WARN_WAITING_FOR_OTHER_TX);
     ASSERT_EQ(Status::ERR_CC, rc);
+    //auto* ti = static_cast<session*>(s2);
+    //EXPECT_EQ(ti->get_result_info().get_reason_code(), reason_code::KVS_INSERT);
     ASSERT_EQ(Status::OK, leave(s1));
     ASSERT_EQ(Status::OK, leave(s2));
 }