本文汇总了PolarDB-X上常见的DDL执行问题。

创建表执行出错

DDL的执行是一个分布式处理过程,出错可能导致各个分片表结构不一致,所以需要进行手动清理,详细操作步骤如下:

  1. PolarDB-X会提供基本的错误描述信息,比如语法错误等。如果错误信息太长,则会提示您使用SHOW WARNINGS来查看每个分库执行失败的原因。
  2. 执行SHOW TOPOLOGY命令来查看物理表的拓扑结构。
     SHOW TOPOLOGY FROM multi_db_multi_tbl;
     +------+-----------------+-----------------------+
     | ID   | GROUP_NAME      | TABLE_NAME            |
     +------+-----------------+-----------------------+
     |    0 | corona_qatest_0 | multi_db_multi_tbl_00 |
     |    1 | corona_qatest_0 | multi_db_multi_tbl_01 |
     |    2 | corona_qatest_0 | multi_db_multi_tbl_02 |
     |    3 | corona_qatest_1 | multi_db_multi_tbl_03 |
     |    4 | corona_qatest_1 | multi_db_multi_tbl_04 |
     |    5 | corona_qatest_1 | multi_db_multi_tbl_05 |
     |    6 | corona_qatest_2 | multi_db_multi_tbl_06 |
     |    7 | corona_qatest_2 | multi_db_multi_tbl_07 |
     |    8 | corona_qatest_2 | multi_db_multi_tbl_08 |
     |    9 | corona_qatest_3 | multi_db_multi_tbl_09 |
     |   10 | corona_qatest_3 | multi_db_multi_tbl_10 |
     |   11 | corona_qatest_3 | multi_db_multi_tbl_11 |
     +------+-----------------+-----------------------+
     12 rows in set (0.21 sec)
  3. 执行CHECK TABLE tablename语句来查看逻辑表是否创建成功。例如下面的例子展示了multi_db_multi_tbl的某个物理分表没有创建成功时的情况。
    mysql> check table multi_db_multi_tbl;
    +-------------------------------------------------+-------+----------+---------------------------------------------------------------------------+
    | TABLE                                           | OP    | MSG_TYPE | MSG_TEXT                                                                  |
    +-------------------------------------------------+-------+----------+---------------------------------------------------------------------------+
    | andor_mysql_qatest. multi_db_multi_tbl | check | Error    | Table 'corona_qatest_0. multi_db_multi_tbl_02' doesn't exist |
    +-------------------------------------------------+-------+----------+---------------------------------------------------------------------------+
    1 row in set (0.16 sec)
  4. 使用幂等的方式重新执行建表或删表操作,该操作会创建或删除剩余的物理表。
    CREATE TABLE IF NOT EXISTS table1
    (id int, name varchar(30), primary key(id))
    dbpartition by hash(id);  
    DROP TABLE IF EXISTS table1;

建索引失败或加列失败

建索引失败或加列失败的处理方法跟上面建表失败的处理类似,详情请参见如何正确处理DDL异常