mysql怎么共享读锁

说明

1、MyISAM表的读操作(添加读书锁)不会阻止其他过程对同一表的读操作，但会阻止同一表的写作操作。

2、只有读锁释放后，才能执行其他过程的写作操作。锁释放前不能取其他表。

实例

Transaction-A
mysql> lock table myisam_lock read;
Query OK, 0 rows affected (0.00 sec)
 
mysql> select * from myisam_lock;
9 rows in set (0.00 sec)
 
mysql> select * from innodb_lock;
ERROR 1100 (HY000): Table 'innodb_lock' was not locked with LOCK TABLES
 
mysql> update myisam_lo
ck set v='1001' where k='1';
ERROR 1099 (HY000): Table 'myisam_lock' was locked with a READ lock and can't be updated
 
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)