1分钟搞定超慢SQL
前几天，一个用户的研发人员找到我了，说他们有个SQL语句非常慢，我说多慢？他们说：半个小时也没出结果。于是问他们要了SQL语句和执行计划，SQL语句就不能再这里贴出来了，下面是调整前的执行计划（略去某些细节信息）：
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost |
------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 435 | 15664 |
| 1 | HASH JOIN OUTER | | 1 | 435 | 15664 |
| 2 | NESTED LOOPS OUTER | | 1 | 413 | 14780 |
| 3 | NESTED LOOPS | | 1 | 406 | 14780 |
| 4 | NESTED LOOPS OUTER | | 1 | 386 | 14779 |
| 5 | NESTED LOOPS | | 1 | 382 | 12788 |
| 6 | HASH JOIN RIGHT ANTI | | 1 | 369 | 12788 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 7 | VIEW | | 277K| 3521K| 2420 |
| 8 | NESTED LOOPS OUTER | | 277K| 33M| 2420 |
| 9 | HASH JOIN | | 277K| 31M| 2392 |
| 10 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 11 | HASH JOIN | | 277K| 30M| 2389 |
| 12 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 13 | HASH JOIN | | 277K| 27M| 2382 |
| 14 | INDEX FAST FULL SCAN | | 47 | 611 | 2 |
| 15 | HASH JOIN | | 277K| 23M| 2378 |
| 16 | INDEX FULL SCAN | | 366 | 1830 | 1 |
| 17 | HASH JOIN | | 287K| 23M| 2375 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 18 | HASH JOIN | | 64258 | 2886K| 699 |
| 19 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 20 | TABLE ACCESS FULL | | 64528 | 2268K| 695 |
| 21 | TABLE ACCESS FULL | | 288K| 10M| 800 |
| 22 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 23 | HASH JOIN | | 243K| 82M| 5799 |
| 24 | HASH JOIN | | 62017 | 4360K| 710 |
| 25 | TABLE ACCESS FULL | | 366 | 3660 | 3 |
| 26 | HASH JOIN | | 64305 | 3893K| 706 |
| 27 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 28 | HASH JOIN | | 64575 | 3279K| 702 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 29 | HASH JOIN | | 705 | 11280 | 7 |
| 30 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 31 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 32 | TABLE ACCESS FULL | | 64575 | 2270K| 695 |
| 33 | TABLE ACCESS FULL | | 288K| 78M| 800 |
| 34 | INDEX UNIQUE SCAN | | 1 | 13 | 0 |
| 35 | VIEW PUSHED PREDICATE | | 1 | 4 | 1992 |
| 36 | NESTED LOOPS | | 595 | 105K| 1992 |
| 37 | NESTED LOOPS OUTER | | 617 | 106K| 1992 |
| 38 | NESTED LOOPS SEMI | | 1 | 154 | 1109 |
| 39 | NESTED LOOPS | | 1 | 141 | 5 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 40 | NESTED LOOPS | | 1 | 137 | 5 |
| 41 | NESTED LOOPS OUTER | | 1 | 125 | 4 |
| 42 | NESTED LOOPS | | 1 | 118 | 4 |
| 43 | NESTED LOOPS | | 1 | 111 | 4 |
| 44 | NESTED LOOPS | | 1 | 101 | 3 |
| 45 | NESTED LOOPS | | 1 | 88 | 3 |
| 46 | TABLE ACCESS BY INDEX ROWID | | 1 | 52 | 2 |
| 47 | INDEX UNIQUE SCAN | | 1 | | 1 |
| 48 | TABLE ACCESS BY INDEX ROWID | | 64575 | 2270K| 1 |
| 49 | INDEX UNIQUE SCAN | | 1 | | 0 |
| 50 | INDEX UNIQUE SCAN | | 409 | 5317 | 0 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 51 | TABLE ACCESS BY INDEX ROWID | | 46 | 460 | 1 |
| 52 | INDEX UNIQUE SCAN | | 1 | | 0 |
| 53 | INDEX UNIQUE SCAN | | 1305 | 9135 | 0 |
| 54 | INDEX UNIQUE SCAN | | 73457 | 502K| 0 |
| 55 | TABLE ACCESS BY INDEX ROWID | | 705 | 8460 | 1 |
| 56 | INDEX UNIQUE SCAN | | 1 | | 0 |
| 57 | INDEX UNIQUE SCAN | | 26 | 104 | 0 |
| 58 | VIEW | | 2774 | 36062 | 1104 |
| 59 | NESTED LOOPS | | 2774 | 341K| 1104 |
| 60 | NESTED LOOPS OUTER | | 2774 | 306K| 1104 |
| 61 | NESTED LOOPS | | 2774 | 287K| 1103 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 62 | NESTED LOOPS | | 2876 | 283K| 1103 |
| 63 | HASH JOIN | | 2876 | 272K| 1103 |
| 64 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 65 | HASH JOIN | | 2889 | 245K| 1099 |
| 66 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 67 | HASH JOIN | | 2889 | 211K| 1094 |
| 68 | TABLE ACCESS BY INDEX ROWID| | 2886 | 109K| 398 |
| 69 | INDEX RANGE SCAN | | 1161 | | 7 |
| 70 | TABLE ACCESS FULL | | 64528 | 2268K| 695 |
| 71 | INDEX UNIQUE SCAN | | 1 | 4 | 0 |
| 72 | INDEX RANGE SCAN | | 1 | 5 | 0 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 73 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 74 | INDEX UNIQUE SCAN | | 1 | 13 | 0 |
| 75 | VIEW | | 617 | 13574 | 883 |
| 76 | NESTED LOOPS | | 61721 | 4942K| 883 |
| 77 | HASH JOIN RIGHT OUTER | | 61721 | 4520K| 876 |
| 78 | TABLE ACCESS FULL | | 47281 | 646K| 168 |
| 79 | HASH JOIN | | 61721 | 3676K| 707 |
| 80 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 81 | HASH JOIN | | 61721 | 3435K| 705 |
| 82 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 83 | HASH JOIN | | 61721 | 2712K| 700 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 84 | INDEX FAST FULL SCAN | | 1305 | 9135 | 2 |
| 85 | HASH JOIN | | 62017 | 2301K| 697 |
| 86 | NESTED LOOPS | | 44 | 660 | 3 |
| 87 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 88 | INDEX RANGE SCAN | | 1 | 5 | 0 |
| 89 | TABLE ACCESS FULL | | 64575 | 1450K| 693 |
| 90 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 91 | INDEX RANGE SCAN | | 1 | 5 | 0 |
| 92 | TABLE ACCESS BY INDEX ROWID | | 1 | 20 | 1 |
| 93 | INDEX UNIQUE SCAN | | 1 | | 0 |
| 94 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 95 | VIEW | | 61721 | 1326K| 883 |
| 96 | NESTED LOOPS | | 61721 | 4942K| 883 |
| 97 | HASH JOIN RIGHT OUTER | | 61721 | 4520K| 876 |
| 98 | TABLE ACCESS FULL | | 47281 | 646K| 168 |
| 99 | HASH JOIN | | 61721 | 3676K| 707 |
| 100 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 101 | HASH JOIN | | 61721 | 3435K| 705 |
| 102 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 103 | HASH JOIN | | 61721 | 2712K| 700 |
| 104 | INDEX FAST FULL SCAN | | 1305 | 9135 | 2 |
| 105 | HASH JOIN | | 62017 | 2301K| 697 |
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------
| 106 | NESTED LOOPS | | 44 | 660 | 3 |
| 107 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 108 | INDEX RANGE SCAN | | 1 | 5 | 0 |
| 109 | TABLE ACCESS FULL | | 64575 | 1450K| 693 |
| 110 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
------------------------------------------------------------------------------------------------------
看了下这个较长的计划，心里有数了，略施小计，再看执行计划，已变过来了，也贴在下面（略去某些细节）：
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost |
---------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 131K| 27M| 15293 |
| 1 | HASH JOIN RIGHT OUTER | | 131K| 27M| 15293 |
| 2 | VIEW | | 61721 | 1326K| 883 |
| 3 | NESTED LOOPS | | 61721 | 4942K| 883 |
| 4 | HASH JOIN RIGHT OUTER | | 61721 | 4520K| 876 |
| 5 | TABLE ACCESS FULL | | 47281 | 646K| 168 |
| 6 | HASH JOIN | | 61721 | 3676K| 707 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 7 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 8 | HASH JOIN | | 61721 | 3435K| 705 |
| 9 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 10 | HASH JOIN | | 61721 | 2712K| 700 |
| 11 | INDEX FAST FULL SCAN | | 1305 | 9135 | 2 |
| 12 | HASH JOIN | | 62017 | 2301K| 697 |
| 13 | NESTED LOOPS | | 44 | 660 | 3 |
| 14 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 15 | INDEX RANGE SCAN | | 1 | 5 | 0 |
| 16 | TABLE ACCESS FULL | | 64575 | 1450K| 693 |
| 17 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 18 | HASH JOIN RIGHT OUTER | | 131K| 24M| 13017 |
| 19 | VIEW | | 75387 | 957K| 6876 |
| 20 | HASH JOIN RIGHT OUTER | | 75387 | 10M| 6876 |
| 21 | VIEW | | 61721 | 1326K| 883 |
| 22 | NESTED LOOPS | | 61721 | 4942K| 883 |
| 23 | HASH JOIN RIGHT OUTER | | 61721 | 4520K| 876 |
| 24 | TABLE ACCESS FULL | | 47281 | 646K| 168 |
| 25 | HASH JOIN | | 61721 | 3676K| 707 |
| 26 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 27 | HASH JOIN | | 61721 | 3435K| 705 |
| 28 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 29 | HASH JOIN | | 61721 | 2712K| 700 |
| 30 | INDEX FAST FULL SCAN | | 1305 | 9135 | 2 |
| 31 | HASH JOIN | | 62017 | 2301K| 697 |
| 32 | NESTED LOOPS | | 44 | 660 | 3 |
| 33 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 34 | INDEX RANGE SCAN | | 1 | 5 | 0 |
| 35 | TABLE ACCESS FULL | | 64575 | 1450K| 693 |
| 36 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 37 | NESTED LOOPS OUTER | | 75387 | 9644K| 5381 |
| 38 | HASH JOIN | | 75387 | 9128K| 5373 |
| 39 | INDEX FAST FULL SCAN | | 47 | 611 | 2 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 40 | HASH JOIN | | 75387 | 8171K| 5370 |
| 41 | INDEX FAST FULL SCAN | | 1305 | 9135 | 2 |
| 42 | HASH JOIN | | 75750 | 7693K| 5367 |
| 43 | INDEX FULL SCAN | | 366 | 1830 | 1 |
| 44 | HASH JOIN RIGHT SEMI | | 78544 | 7593K| 5365 |
| 45 | VIEW | | 208K| 2643K| 2011 |
| 46 | NESTED LOOPS OUTER | | 208K| 20M| 2011 |
| 47 | HASH JOIN | | 208K| 19M| 1990 |
| 48 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 49 | HASH JOIN | | 208K| 18M| 1988 |
| 50 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 51 | HASH JOIN | | 208K| 16M| 1981 |
| 52 | INDEX FAST FULL SCAN| | 47 | 611 | 2 |
| 53 | HASH JOIN | | 208K| 13M| 1977 |
| 54 | INDEX FULL SCAN | | 366 | 1830 | 1 |
| 55 | HASH JOIN | | 215K| 12M| 1975 |
| 56 | HASH JOIN | | 64258 | 2886K| 699 |
| 57 | TABLE ACCESS FULL| | 46 | 460 | 3 |
| 58 | TABLE ACCESS FULL| | 64528 | 2268K| 695 |
| 59 | TABLE ACCESS FULL | | 216K| 3595K| 798 |
| 60 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 61 | HASH JOIN | | 215K| 17M| 2102 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 62 | HASH JOIN | | 64305 | 3893K| 706 |
| 63 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 64 | HASH JOIN | | 64575 | 3279K| 702 |
| 65 | HASH JOIN | | 705 | 11280 | 7 |
| 66 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 67 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 68 | TABLE ACCESS FULL | | 64575 | 2270K| 695 |
| 69 | TABLE ACCESS FULL | | 216K| 5076K| 798 |
| 70 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 71 | NESTED LOOPS OUTER | | 131K| 22M| 6139 |
| 72 | HASH JOIN | | 131K| 22M| 6126 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 73 | INDEX FAST FULL SCAN | | 47 | 611 | 2 |
| 74 | HASH JOIN | | 131K| 20M| 6123 |
| 75 | TABLE ACCESS FULL | | 1305 | 26100 | 5 |
| 76 | HASH JOIN RIGHT ANTI | | 132K| 17M| 6117 |
| 77 | VIEW | | 208K| 2643K| 2011 |
| 78 | NESTED LOOPS OUTER | | 208K| 20M| 2011 |
| 79 | HASH JOIN | | 208K| 19M| 1990 |
| 80 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 81 | HASH JOIN | | 208K| 18M| 1988 |
| 82 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 83 | HASH JOIN | | 208K| 16M| 1981 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 84 | INDEX FAST FULL SCAN | | 47 | 611 | 2 |
| 85 | HASH JOIN | | 208K| 13M| 1977 |
| 86 | INDEX FULL SCAN | | 366 | 1830 | 1 |
| 87 | HASH JOIN | | 215K| 12M| 1975 |
| 88 | HASH JOIN | | 64258 | 2886K| 699 |
| 89 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 90 | TABLE ACCESS FULL | | 64528 | 2268K| 695 |
| 91 | TABLE ACCESS FULL | | 216K| 3595K| 798 |
| 92 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
| 93 | HASH JOIN | | 208K| 25M| 2465 |
| 94 | HASH JOIN | | 62017 | 4360K| 710 |
PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------
| 95 | TABLE ACCESS FULL | | 366 | 3660 | 3 |
| 96 | HASH JOIN | | 64305 | 3893K| 706 |
| 97 | TABLE ACCESS FULL | | 46 | 460 | 3 |
| 98 | HASH JOIN | | 64575 | 3279K| 702 |
| 99 | HASH JOIN | | 705 | 11280 | 7 |
| 100 | INDEX FULL SCAN | | 26 | 104 | 1 |
| 101 | TABLE ACCESS FULL | | 705 | 8460 | 5 |
| 102 | TABLE ACCESS FULL | | 64575 | 2270K| 695 |
| 103 | TABLE ACCESS FULL | | 216K| 11M| 798 |
| 104 | INDEX UNIQUE SCAN | | 1 | 7 | 0 |
---------------------------------------------------------------------------------------------
既然执行计划变过来了，那么试下效果：1~2s出结果，用户说这样的效果可以，问题到此搞定，总共过程不过几分钟，面对这么大的一个执行计划，肯定需要经验才可以判断问题所在，进而想出相应的办法解决，大家可以对比参考学习，禁止转载。
1分钟搞定超慢SQL的更多相关文章
- 快速SQL调优/优化（SQL TUNING）——1分钟搞定超慢SQL
前几天,一个用户的研发人员找到我了,说他们有个SQL语句非常慢,我说多慢?他们说:半个小时也没出结果.于是问他们要了SQL语句和执行计划,SQL语句就不能再这里贴出来了,下面是调整前的执行计划(略去某 ...
- windows+mysql集群搭建-三分钟搞定集群
注:本文来源: 陈晓婵 < windows+mysql集群搭建-三分钟搞定集群 > 一:mysql集群搭建教程-基础篇 计算机一级考试系统要用集群,目标是把集群搭建起来,保证一 ...
- JS组件系列——又一款MVVM组件：Vue（一：30分钟搞定前端增删改查）
前言:关于Vue框架,好几个月之前就听说过,了解一项新技术之后,总是处于观望状态,一直在犹豫要不要系统学习下.正好最近有点空,就去官网了解了下,看上去还不错的一个组件,就抽空研究了下.最近园子里vue ...
- 一分钟搞定AlloyTouch图片轮播
一分钟搞定AlloyTouch图片轮播 轮播图也涉及到触摸和触摸反馈,同时,AlloyTouch可以把惯性运动打开或者关闭,并且设置min和max为运动区域,超出会自动回弹.除了一般的竖向滚动,A ...
- 五分钟搞定Go.js
五分钟搞定Go.js 1.基于html5~因为Go.js是一个依赖于HTML5特性的JavaScript库,所以需要确保您的页面声明它是一个HTML5文档,当然需要加载库 <!DOCTYPE ...
- Spring Boot 返回 XML 数据，一分钟搞定！
Spring Boot 返回 XML 数据,前提必须已经搭建了 Spring Boot 项目,所以这一块代码就不贴了,可以点击查看之前分享的 Spring Boot 返回 JSON 数据,一分钟搞定! ...
- zookeeper-架构设计与角色分工-《每日五分钟搞定大数据》
本篇文章阅读时间5分钟左右 点击看<每日五分钟搞定大数据>完整思维导图 zookeeper作为一个分布式协调系统,很多组件都会依赖它,那么此时它的可用性就非常重要了,那么保证可用性的同 ...
- zookeeper核心-zab协议-《每日五分钟搞定大数据》
上篇文章<paxos与一致性>说到zab是在paxos的基础上做了重要的改造,解决了一系列的问题,这一篇我们就来说下这个zab. zab协议的全称是ZooKeeper Atomic Bro ...
- 十分钟搞定pandas内容
目录 十分钟搞定pandas 一.创建对象 二.查看数据 三.选择器 十二.导入和保存数据 参考:http://pandas.pydata.org/pandas-docs/stable/whatsne ...
随机推荐
- 实现php获取mp3文件元信息如播放时间歌曲作者等
最近收集到一个php获取mp3文件元信息的类,感觉比较方便.现在分享给大家! 下面是使用方式和测试方式: <?php include_once 'mp3file.class.php'; func ...
- hadoop笔记之Hive的数据存储(视图)
Hive的数据存储(视图) Hive的数据存储(视图) 视图(view) 视图是一种虚表,是一个逻辑概念:可以跨越多张表 既然视图是一种虚表,那么也就是说用操作表的方式也可以操作视图 但是视图是建立在 ...
- Extjs Store 的用法详解
Ext.data.Store的基本用法 在使用之前,首先要创建一个Ext.data.Store的实例,如下面的代码所示. 每个store最少需要两个组件的支持,分别是proxy和reade ...
- 网站linux.linuxidc.com有很多好资料
免费下载地址在 http://linux.linuxidc.com/ 用户名与密码都是www.linuxidc.com 有一些介绍:www.linuxidc.com/download
- java.util.Random 类的 nextInt(int num )
随机产生3个67~295的整数并找出数值居中的数 并输出中间的数例如:100,225和200,输出200 要随机产生某个范围内的整数,用 java.util.Random 类的 nextInt(int ...
- MarkWord
MarkWord - 可发布博客的 Markdown编辑器 代码开源 1 /// <summary> 2 /// 同步呈现 3 /// </summary> 4 /// < ...
- EntityFramework、Dapper vs 草根框架性能
EntityFramework.Dapper vs 草根框架性能 扯淡 当前市面上 ORM 很多,有跑车型的,如 Dapper,有中规中矩型的,如 Mybatis.Net,也有重量型的,如 Entit ...
- 8. java.lang.ArithmeticException
java.lang.ArithmeticException 数学运算异常 当算术运算中出现了除以零这样的运算就会出这样的异常.
- KPI考核
编辑 本词条缺少名片图,补充相关内容使词条更完整,还能快速升级,赶紧来编辑吧! KPI考核,Key Performance Indicator的缩写,指的是关键绩效指标考核法. 中文名 KPI考核 外 ...
- Android之CookieStore的持久化
CookieStore是一个对象,有的服务端 ,比如.net,保持登录状态不是用httpclient.addHeader(“cookie”,SessionId),而是用httppost.setCook ...