ENGINES
ENGINES 表提供关于存储引擎的信息。为了兼容性，TiDB 始终将 InnoDB 描述为唯一支持的引擎。此外，ENGINES 表中的其他列值也都是固定值。
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 表中各列的描述如下：
ENGINES：存储引擎的名称。SUPPORT：服务器对存储引擎的支持程度。在 TiDB 中，该值始终为DEFAULT。COMMENT：关于存储引擎的简要说明。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。