:original_name: ddm_01_0175.html

.. _ddm_01_0175:

High-risk Operations
====================

Pay attention to the following when you use DDM:

-  Do not connect to any data node for data operations to avoid deleting by mistake system catalogs or metadata.
-  Do not clear system tables **TBL_DRDS_TABLE** and **MYCAT_SEQUENCE** to prevent metadata loss.