存储引擎
查看引擎：
show engines;
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| mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)
|
查看当前mysql默认存储引擎：
show variables like '%storage_engine%';
对比项 MyISAM InnoDB
主外键 不支持 支持
事务 不支持 支持
行表锁 表锁，即操作一条记录会锁住整张表 行锁
不适合高并发操作
缓存 只缓存索引，不缓存真实数据 不仅缓存索引还缓存数据，对内存的要求较高
而内存的大小对性能有决定性影响
表空间 小 大
关注点 性能 事务
默认安装 Y Y
