zoukankan      html  css  js  c++  java
  • MySQL分区实验

    环境 CentOS5.5,内存256MB,MySQL5.5.16

    一、创建测试表

    CREATE TABLE part_tab(
        c1 INT DEFAULT NULL,
        c2 VARCHAR(30) DEFAULT NULL,
        c3 DATE DEFAULT NULL
    ) ENGINE=myisam CHARSET=utf8
    partition by RANGE(YEAR(c3))(
    partition p0 values less than(1995),
    partition p1 values less than(1996),
    partition p2 values less than(1997),
    partition p3 values less than(1998),
    partition p4 values less than(1999),
    partition p5 values less than(2000),
    partition p6 values less than(2001),
    partition p7 values less than(2002),
    partition p8 values less than(2003),
    partition p9 values less than(2004),
    partition p10 values less than(2010),
    partition p11 values less than MAXVALUE)
    CREATE TABLE `no_part_tab` (
      `c1` int(11) DEFAULT NULL,
      `c2` varchar(30) DEFAULT NULL,
      `c3` date DEFAULT NULL
    ) ENGINE=MyISAM DEFAULT CHARSET=utf8;

    二、创建测试数据

    CREATE PROCEDURE `p1`()
    begin
        declare v int default 0;
        while v<8000000 do
        insert into part_tab values (v,'testing partition',adddate('1995-01-01',(rand(v)*36520) mod 3652));
        set v=v+1;
        end while;
    end

      call p1;

      insert into no_part_tab select * from part_tab

    三、测试

      select count(*) from part_tab where c3>date '1995-01-01' and c3< date '1995-12-31';  #1.875s

      select count(*) from no_part_tab where c3>date '1995-01-01' and c3< date '1995-12-31';  #9.269s

    四、分析

      desc select count(*) from part_tab where c3>date '1995-01-01' and c3< date '1995-12-31' G;

      

      desc select count(*) from no_part_tab where c3>date '1995-01-01' and c3< date '1995-12-31' G;

      

      可以看出慢的原因了

    五、创建索引再测试

      create index idx_of_c3 on part_tab(c3);

      create index idx_of_c3 on no_part_tab(c3);

      select count(*) from no_part_tab where c3>date '1995-01-01' and c3< date '1995-12-31';  #1.49s

      select count(*) from part_tab where c3>date '1995-01-01' and c3< date '1995-12-31';    #1.48s

      查询时间差不多,分析图就想想就知道样子了

    六、使用未索引字段查询

      select count(*) from no_part_tab where c3>date '1995-01-01' and c3< date '1996-12-31' and c2='hello';  #12.274s

      select count(*) from part_tab where c3>date '1995-01-01' and c3< date '1996-12-31' and c2='hello';    #2.74s

    七、分析

      

      

    八、总结

      在数据量较大的情况 使用被作为查询条件较频繁的字段 作为分区的依据。

  • 相关阅读:
    关于 IIS 上运行 ASP.NET Core 站点的“HTTP 错误 500.19”错误
    下单快发货慢:一个 JOIN SQL 引起 SqlClient 读取数据慢的奇特问题
    ASP.NET Core 2.2 项目升级至 3.0 备忘录
    corefx 源码学习:SqlClient 是如何同步建立 Socket 连接的
    Chimee
    electron-vue:Vue.js 开发 Electron 桌面应用
    H5网页适配 iPhoneX,就是这么简单
    经典文摘:饿了么的 PWA 升级实践(结合Vue.js)
    Table Dragger
    分享8个网站开发中最好用的打印页面插件
  • 原文地址:https://www.cnblogs.com/hwt987/p/3677237.html
Copyright © 2011-2022 走看看