diff --git a/src/obproxy/proxy/mysql/ob_mysql_sm.cpp b/src/obproxy/proxy/mysql/ob_mysql_sm.cpp
index 3297af19..3190a123 100644
--- a/src/obproxy/proxy/mysql/ob_mysql_sm.cpp
+++ b/src/obproxy/proxy/mysql/ob_mysql_sm.cpp
@@ -9532,7 +9532,6 @@ inline void ObMysqlSM::update_monitor_log()
         }
 
         if (is_error_resp) {
-          const ObString &server_trace_id = get_server_trace_id();
           _OBPROXY_ERROR_LOG(WARN, MONITOR_ERROR_LOG_FORMAT, MONITOR_ERROR_LOG_PARAM);
         }
       }