MySQL数据库Event定时执行任务详解

一、背景

  由于项目的业务是不断往前跑的，所以难免数据库的表的量会越来越庞大，不断的挤占硬盘空间。即使再大的空间也支撑不起业务的增长，所以定期删除不必要的数据是很有必要的。在我们项目中由于不清理数据，一个表占的空间竟然达到了4g之多。想想有多可怕...

  这里介绍的是用mysql 建立一个定时器event，定期清除掉之前的不必要事件。

二、内容

#1、建立存储过程供事件调用
delimiter//
drop procedure if exists middle_proce//
create procedure middle_proce()
begin
delete from jg_bj_comit_log where comit_time < subdate(now(),interval 2 month);
optimize table jg_bj_comit_log;
delete from jg_bj_order_create where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_order_create;
delete from jg_bj_order_match where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_order_match;
delete from jg_bj_order_cancel where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_order_cancel;
delete from jg_bj_operate_arrive where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_operate_arrive;
delete from jg_bj_operate_depart where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_operate_depart;
delete from jg_bj_operate_login where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_operate_login;
delete from jg_bj_operate_logout where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_operate_logout;
delete from jg_bj_operate_pay where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_operate_pay;
delete from jg_bj_position_driver where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_position_driver;
delete from jg_bj_position_vehicle where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_position_vehicle;
delete from jg_bj_rated_passenger where created_on < subdate(now(),interval 3 month);
optimize table jg_bj_rated_passenger;
end//
delimiter;

#2、开启event(要使定时起作用，mysql的常量global event_schduleer 必须为on 或者1)
show variables like 'event_scheduler'
set global event_scheduler='on'

#3、创建evnet事件
drop event if exists middle_event;
create event middle_event
on schedule every 1 day starts '2017-12-05 00:00:01'
on completion preserve enable
do call middle_proce();

#4、开启event 事件
alter event middle_event on completion preserve enable;

#5、关闭event 事件
alter event middle_event on completion preserve disable;

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。