Mysql:
show full processlist; //看所有进程
show status like 'Threads%'; //看所有连接
show global variables like 'wait_timeout'; //mysql看sleep自动断开时长
show open tables where in_use > 0; //查看被锁的表
show variables like 'log%'; //看日志路径
select current_timestamp(); //看当前时间
https://www.nowcoder.com/ta/coding-interviews //笔试题
pip install matplotlib -i https://pypi.tuna.tsinghua.edu.cn/simple