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mysql数据库存储引擎（1）
mysql的存储引擎就是指表的类型。数据库的存储引擎决定了表在计算机中的存储方式。
首先我们可以查看mysql支持的存储引擎：
mysql> show engines; +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | InnoDB | YES | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | MRG_MYISAM | YES | Collection of identical MyISAM tables | 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 | | FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | | MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 8 rows in set (0.00 sec) mysql> show engines\g +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ | InnoDB | YES | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | MRG_MYISAM | YES | Collection of identical MyISAM tables | 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 | | FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | | MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO | +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 8 rows in set (0.00 sec)
show engines语句可以以“；”号结尾，也可以使用“\g”或者“\G”。“\G”的效果使结果看起来更加美观。如下：
mysql> show engines\G *************************** 1. row *************************** Engine: InnoDB Support: YES Comment: Supports transactions, row-level locking, and foreign keys Transactions: YES XA: YES Savepoints: YES *************************** 2. row *************************** Engine: MRG_MYISAM Support: YES Comment: Collection of identical MyISAM tables Transactions: NO XA: NO Savepoints: NO *************************** 3. row *************************** Engine: BLACKHOLE Support: YES Comment: /dev/null storage engine (anything you write to it disappears) Transactions: NO XA: NO Savepoints: NO *************************** 4. row *************************** Engine: CSV Support: YES Comment: CSV storage engine Transactions: NO XA: NO Savepoints: NO *************************** 5. row *************************** Engine: MEMORY Support: YES Comment: Hash based, stored in memory, useful for temporary tables Transactions: NO XA: NO Savepoints: NO *************************** 6. row *************************** Engine: FEDERATED Support: NO Comment: Federated MySQL storage engine Transactions: NULL XA: NULL Savepoints: NULL *************************** 7. row *************************** Engine: ARCHIVE Support: YES Comment: Archive storage engine Transactions: NO XA: NO Savepoints: NO *************************** 8. row *************************** Engine: MyISAM Support: DEFAULT Comment: Default engine as of MySQL 3.23 with great performance Transactions: NO XA: NO Savepoints: NO 8 rows in set (0.00 sec) mysql>
查询结果中，engine参数指存储引擎的名称，support说明mysql是否支持该类引擎；comment是对该引擎的评论；Transaction表示是否支持事务处理；XA表示是否分布式交易出了XA规范，savepoint参数表示是否支持保存点，以便事务回滚到保存点。
还可以使用以下语句查看mysql支持的引擎：
mysql> show variables like ‘have%‘; +-------------------------+----------+ | Variable_name | Value | +-------------------------+----------+ | have_community_features | YES | | have_compress | YES | | have_crypt | YES | | have_csv | YES | | have_dynamic_loading | YES | | have_geometry | YES | | have_innodb | YES | | have_ndbcluster | NO | | have_openssl | DISABLED | | have_partitioning | YES | | have_query_cache | YES | | have_rtree_keys | YES | | have_ssl | DISABLED | | have_symlink | YES | +-------------------------+----------+ 14 rows in set (0.00 sec) mysql>
第一列表示引擎名称，第二列value表示mysql的支持情况。yes表示支持，no表示不支持，disabled表示支持但还没有开启。
查看当前mysql的默认引擎：
mysql> show variables like ‘storage_engine‘; +----------------+--------+ | Variable_name | Value | +----------------+--------+ | storage_engine | MyISAM | +----------------+--------+ 1 row in set (0.00 sec) mysql> show variables like ‘storage_engine‘\G *************************** 1. row *************************** Variable_name: storage_engine Value: MyISAM 1 row in set (0.00 sec) mysql>
在创建表时，若没有指定表的存储引擎，表的存储引擎将为默认的存储引擎。
本文出自 “自定义” 博客，谢绝转载！
mysql数据库存储引擎（1）
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