Modify Configuration Online: change a name

Author: en-jin19

dynamic-config.md

@@ -272,9 +272,11 @@ For detailed parameter description, refer to [PD Configuration File](/pd-configu
 
 ### Modify TiDB configuration online
 
-Currently, the method of changing TiDB configuration is different from that of changing TiKV and PD configurations. You can modify TiDB configuration by using [SQL variables](/system-variables.md).
+Currently, the method of changing TiDB configuration is different from that of changing TiKV and PD configurations. You can modify TiDB configuration by using [system variables](/system-variables.md).
 
-The following example shows how to modify `slow-threshold` online by using the `tidb_slow_log_threshold` variable. The default value of `slow-threshold` is 200 ms. You can set it to 200 ms by using `tidb_slow_log_threshold`.
+The following example shows how to modify `slow-threshold` online by using the `tidb_slow_log_threshold` variable. 
+
+The default value of `slow-threshold` is 300 ms. You can set it to 200 ms by using `tidb_slow_log_threshold`.
 
 {{< copyable "sql" >}}