ENGINES

ENGINES 表提供了关于存储引擎的信息。从和 MySQL 兼容性上考虑,TiDB 会一直将 InnoDB 描述为唯一支持的引擎。此外,ENGINES 表中其它列值也都是定值。

USE information_schema; DESC engines;
+--------------+-------------+------+------+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------+-------------+------+------+---------+-------+ | ENGINE | varchar(64) | YES | | NULL | | | SUPPORT | varchar(8) | YES | | NULL | | | COMMENT | varchar(80) | YES | | NULL | | | TRANSACTIONS | varchar(3) | YES | | NULL | | | XA | varchar(3) | YES | | NULL | | | SAVEPOINTS | varchar(3) | YES | | NULL | | +--------------+-------------+------+------+---------+-------+ 6 rows in set (0.00 sec)
SELECT * FROM engines;
+--------+---------+------------------------------------------------------------+--------------+------+------------+ | ENGINE | SUPPORT | COMMENT | TRANSACTIONS | XA | SAVEPOINTS | +--------+---------+------------------------------------------------------------+--------------+------+------------+ | InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | +--------+---------+------------------------------------------------------------+--------------+------+------------+ 1 row in set (0.01 sec)

ENGINES 表中列的含义如下:

  • ENGINE:存储引擎的名称。
  • SUPPORT:服务器对存储引擎的支持级别,在 TiDB 中此值一直是 DEFAULT
  • COMMENT:存储引擎的简要描述。
  • TRANSACTIONS:存储引擎是否支持事务。
  • XA:存储引擎是否支持 XA 事务。
  • SAVEPOINTS:存储引擎是否支持 savepoints