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实战低成本服务器搭建千万级数据采集系统 - 更多技术 - 清泛网 - 专注C/C++...
...oncrawler上一篇文章《社会化海量数据采集框架搭建》提到如何搭建一个社会化采集系统架构,讲架构一般都比较虚,这一篇讲一下如何实战用低成本服务器...有这样一个采集系统的需求,达成指标: 需要采集30万关键词的数据 ...
Visual SVN 安装及客户端使用 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...,没有任何内容在里面。我会在这个教程的第二部分说明如何迁入源代码。
下面,我们开始安全性设置,在左侧的Users上点击右键:
输入上面的信息,点击OK,我们就创建一个用户了。按照上面的过程,分别添加用户Develo...
淘宝大秒系统设计详解 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...进行动静分离,这也是解决大流量系统的一个重要原则。如何给系统做动静分离的静态化改造我以前写过一篇《高访问量系统的静态化架构设计》详细介绍了淘宝商品系统的静态化设计思路,感兴趣的可以在《程序员》杂志上找...
What is the difference between UNION and UNION ALL?
...want the duplicates (especially when developing reports).
UNION Example:
SELECT 'foo' AS bar UNION SELECT 'foo' AS bar
Result:
+-----+
| bar |
+-----+
| foo |
+-----+
1 row in set (0.00 sec)
UNION ALL example:
SELECT 'foo' AS bar UNION ALL SELECT 'foo' AS bar
Result:
+-----+
| bar |
+---...
django test app error - Got an error creating the test database: permission denied to create databas
...@localhost; I originally tried to only GRANT CREATE... but then could not SELECT or DROP the created database. This essentially makes your user a superuser, so be careful.
– mightypile
Dec 31 '15 at 16:28
...
What's the difference between RANK() and DENSE_RANK() functions in oracle?
...s a simple test script you can play with to see what happens:
with q as (
select 10 deptno, 'rrr' empname, 10000.00 sal from dual union all
select 11, 'nnn', 20000.00 from dual union all
select 11, 'mmm', 5000.00 from dual union all
select 12, 'kkk', 30000 from dual union all
select 10, 'fff', 4000...
How to convert DateTime to VarChar
...yDateTime DATETIME
SET @myDateTime = '2008-05-03'
--
-- Convert string
--
SELECT LEFT(CONVERT(VARCHAR, @myDateTime, 120), 10)
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How to perform a mysqldump without a password prompt?
...and in no case the root user. It can be done like this: GRANT LOCK TABLES, SELECT ON *.* TO 'BACKUPUSER'@'%' IDENTIFIED BY 'PASSWORD';
– gadjou
Feb 21 '17 at 8:34
...
Favourite performance tuning tricks [closed]
...n-optimal query plan
Break up the Join
Can you break up the join?
Pre-select foreign keys into a temporary table
Do half the join and put results in a temporary table
Are you using the right kind of temporary table?
#temp tables may perform much better than @table variables with large volum...
项目管理实践教程二、源代码控制【Source Control Using VisualSVN Server ...
...,没有任何内容在里面。我会在这个教程的第二部分说明如何迁入源代码。
下面,我们开始安全性设置,在左侧的Users上点击右键:
输入上面的信息,点击OK,我们就创建一个用户了。按照上面的过程,分别添加用户Develo...
