为什么需要索引(Why is it needed)?当数据保存在磁盘类存储介质上时,它是作为数据块存放。这些数据块是被当作一个整体来访问的,这样可以保证操作的原子性。硬盘数据块存储结构类似于链表,都包含数据部分,以及一个指向下一个节点(或数据块)的指针,不需要连续存储。记录集只能在某个关键字段上进行...
分类:
数据库 时间:
2015-09-15 01:37:15
阅读次数:
147
spark 恢复机制使用的监控 https://mmonit.com/monit/ Up and running in 15 minutes! With all features needed for system monitoring and error recovery. It‘s like having a watchdog with a toolbox on you...
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其他好文 时间:
2015-09-07 18:06:11
阅读次数:
130
It is often appropriate to reuse a single object instead of creating a new functionally equivalent object each time it is needed.Reuse can be both fas...
分类:
编程语言 时间:
2015-09-06 14:32:40
阅读次数:
184
购买Nexus手机的朋友大多是为了自己修改系统玩,再加上其较高的性价比,在开发者中还是广受欢迎的。我的5太子被我升级到了6.0预览版,玩的正嗨,舍不得换回到5.1时代了。不过鉴于距6.0源码发布还有段日子,5.1的源码编译与烧写仍是主流,下面就记录了整个过程(持续了很长时间,我们要有耐心)。搭建开发环境系统推荐Ubuntu 14.04
1.openjdk is needed$ sudo apt-g...
分类:
移动开发 时间:
2015-09-04 07:37:09
阅读次数:
278
It can be tedious to type out all the boilerplate needed to get the DOM and states inReactto synchronize. Luckily, React provides a version of the too...
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其他好文 时间:
2015-09-02 20:35:48
阅读次数:
287
使用service tomcat-web1 start命令报下面的错误
Neither the JAVA_HOME nor the JRE_HOME environment variable is defined. At least one of these environment variable is needed to run this program...
分类:
数据库 时间:
2015-08-21 19:36:23
阅读次数:
234
默认情况下,无法建立多层目录
[huage@localhost ~]$ mkdir -p 3/4/5
加了-p参数后可以直接建立多层目录
-p, --parents
no error if existing, make parent directories as needed...
分类:
系统相关 时间:
2015-08-15 20:07:11
阅读次数:
237
The idea is to search for the left and right boundaries of target via two binary searches. Well, some tricks may be needed. Take a look at this link :...
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其他好文 时间:
2015-08-15 18:10:48
阅读次数:
96
Description
Little girl Susie went shopping with her mom and she wondered how to improve service quality.
There are n people in the queue. For each person we know time ti needed
to serve him. A ...
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其他好文 时间:
2015-08-15 16:39:37
阅读次数:
112
安装SALT时,需要这样作,公司有一批REDHAT5的,弄起来。。。然后却是:Missing Dependency: python(abi) = 2.6 is needed by packagerpm -q --provides python | grep abipython(abi) = 2.4过...
分类:
编程语言 时间:
2015-08-14 15:21:55
阅读次数:
143