select count(*) from person_info_large;
select count(*) from person_info_myisam;
select * from person_info_myisam where id between 1 and 2000000;
update person_info_myisam set account = account where id = 2000001;
上一个表锁,读锁不释放的话,写锁会被阻塞。
lock table person_info_myisam read | write;
unlock tables;