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Mysql 常用语句

· 2 min read
Innocence

Mysql的infromation_schema库，可以查询数据库中每个表占用的空间、表记录行数

  • TABLE_SCHEMA: 数据库名
  • TABLE_NAME: 表名
  • ENGINE: 使用的存储引擎
  • TABLES_ROWS: 记录数
  • DATA_LENGTH: 数据大小
  • INDEX_LENGTH: 索引大小

查看所有库大小​

use information_schema;
select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data  from TABLES;

查看指定库大小​

select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data  from TABLES where table_schema='xxx';

查看指定库的指定表的大小​

select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as data  from TABLES where table_schema='xxx' and table_name='xxx';

查看指定库的索引大小​

SELECT CONCAT(ROUND(SUM(index_length)/(1024*1024), 2), ' MB') AS 'Total Index Size' FROM TABLES  WHERE table_schema = 'xxx';

查看指定库的指定表的索引大小​

SELECT CONCAT(ROUND(SUM(index_length)/(1024*1024), 2), ' MB') AS 'Total Index Size' FROM TABLES  WHERE table_schema = 'xxx' and table_name='xxx';

查看一个库中的情况​

SELECT CONCAT(table_schema,'.',table_name) AS 'Table Name', CONCAT(ROUND(table_rows/1000000,4),'M') AS 'Number of Rows', CONCAT(ROUND(data_length/(1024*1024*1024),4),'G') AS 'Data Size', CONCAT(ROUND(index_length/(1024*1024*1024),4),'G') AS 'Index Size', CONCAT(ROUND((data_length+index_length)/(1024*1024*1024),4),'G') AS'Total'FROM information_schema.TABLES WHERE table_schema LIKE 'xxx';

查看非 Sleep 状态的链接，按消耗时间倒序展示​

使用show full processlist可以查看所有链接情况

select id, db, user, host, command, time, state, info
from information_schema.processlist
where command != 'Sleep'
order by time desc;

查询执行时间超过2分钟的线程，然后拼接成kill语句​

select concat('kill ', id, ';')
from information_schema.processlist
where command != 'Sleep'
and time > 2*60
order by time desc;

快速杀死所有进程​

mysql -e "show full processlist;" -ss | awk '{print "KILL "$1";"}'| mysql