mysql慢查询日记开启

SHOW VARIABLES LIKE '%slow_query_log%'  //查看


SET GLOBAL slow_query_log=1;//开启


SELECT SLEEP(5)


set global long_query_time=3;//设置慢的阀值时间


SHOW VARIABLES LIKE '%long_query_time%';


SHOW global VARIABLES LIKE '%long_query_time%';


SHOW VARIABLES LIKE 'profiling'


set profiling=on/off;


SHOW PROFILES;



lock table mylock read,book write;//锁表mylock为读锁（共享锁），book表为写锁（排它锁）
show open tables;


unlock tables;


show variables like 'tx_isolation';//查看事务隔离级别


select * from test_innodb_lock where a=8 for update;//锁一行数据