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<title>Yeeach.com掘客 / 话题 / 技术-数据库</title>
<link>http://www.yeeach.com/digg</link>
<description>Pligg Web 2.0 Content Management System  votes</description>
<pubDate>Thu, 28 Aug 2008 04:23:52 PDT</pubDate>
<language>en</language>
<item>
<title><![CDATA[开源数据库 Sharding 技术]]></title>
<link>http://www.yeeach.com/digg/story/854</link>
<comments>http://www.yeeach.com/digg/story/854</comments>
<pubDate>Thu, 28 Aug 2008 04:23:52 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/854</guid>
<description><![CDATA[此文首发于 《程序员》杂志 2008 年 7 月刊。  从 Shard 到 Sharding   &amp;quot;Shard&amp;quot; 这个词英文的意思是&amp;quot;碎片&amp;quot;，而作为数据库相关的技术用语，似乎最早见于大型多人在线角色扮演游戏(MMORPG)中。&amp;quot;Sharding&amp;quot; 姑且称之为&amp;quot;分片&amp;quot;。  Sharding 不是一门新技术，而是一个相对简朴的软件理念。如您所知，MySQL 5 之后才有了数据表分区功能，那么在此之前，很多 MySQL 的潜在用户都对 MySQL 的扩展性有所顾虑，而是否具备分区功能就成了衡量一个数据库可扩展性与否的一个关键指标(当然不是唯一指标)。数据库扩展性是一个永恒的话题，MySQL 的推广者经常会被问到：如在单一数据库上处理应用数据捉襟见肘而需要进行分区化之类的处理，是如何办到的呢? 答案是：Sharding。  Sharding 不是一个某个特定数据库软件附属的功能，而是在具体技术细节之上的抽象处理，是水平扩展(Scale Out，亦或横向扩展、向外扩展)的解决方案，<br/><br/>1 投票人数 ]]></description>
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<item>
<title><![CDATA[MySQL Database Optimization]]></title>
<link>http://www.yeeach.com/digg/story/626</link>
<comments>http://www.yeeach.com/digg/story/626</comments>
<pubDate>Wed, 09 Jul 2008 08:38:53 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/626</guid>
<description><![CDATA[MySQL database optimization is one of the major part of web development. Basically those developers who deals with heavy traffic based web development, will need such optimization. There are very few web tutorial regarding this. I was searching for such tutorial for some purpose with my work. i share those sites contents with you through their full reference. 10 great articles for optimizing MySQL&amp;nbsp;queries  This site includes some wonderful tutorial regardi<br/><br/>1 投票人数 ]]></description>
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<item>
<title><![CDATA[Top10 SQL Performance Tips]]></title>
<link>http://www.yeeach.com/digg/story/486</link>
<comments>http://www.yeeach.com/digg/story/486</comments>
<pubDate>Tue, 22 Apr 2008 08:00:13 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/486</guid>
<description><![CDATA[Specific Query Performance Tips (see also database design tips for tips on indexes):  Use EXPLAIN to profile the query execution plan   Use Slow Query Log (always have it on!)   Don't use DISTINCT when you have or could use GROUP BY  Insert performance  Batch INSERT and REPLACE  Use LOAD DATA in<br/><br/>1 投票人数 ]]></description>
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<item>
<title><![CDATA[MyISAM表锁]]></title>
<link>http://www.yeeach.com/digg/story/454</link>
<comments>http://www.yeeach.com/digg/story/454</comments>
<pubDate>Sat, 05 Apr 2008 05:59:55 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/454</guid>
<description><![CDATA[MyISAM存储引擎只支持表锁，这也是MySQL开始几个版本中唯一支持的 锁类型。随着应用对事务完整性和并发性要求的不断提高，MySQL才开始开发基于事务的存储引擎，后来慢慢出现了支持页锁的BDB存储引擎和支持行锁的 InnoDB存储引擎（实际InnoDB是单独的一个公司，现在已经被Oracle公司收购）。但是MyISAM的表锁依然是使用最为广泛的锁类型。本节 将详细介绍MyISAM表锁的使用。  查询表级锁争用情况  可以通过检查table_locks_waited和table_locks_immediate状态变量来分析系统上的表锁定争夺：  mysql&amp;gt; show status like 'table%';<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[MySQL查询优化系列讲座之调度和锁定]]></title>
<link>http://www.yeeach.com/digg/story/456</link>
<comments>http://www.yeeach.com/digg/story/456</comments>
<pubDate>Sat, 05 Apr 2008 05:59:54 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/456</guid>
<description><![CDATA[前面的部分主要是聚焦于如何让单独的查询执行的速度更快。MySQL还允许你改变语句调度的优先级，它可以使来自多个客户端的查询更好地协作，这样 单个客户端就不会由于锁定而等待很长时间。改变优先级还可以确保特定类型的查询被处理得更快。这一部分讲解MySQL的默认的调度策略和可以用来影响这些 策略的选项。它还谈到了并发性插入操作的使用和存储引擎锁定层次对客户端的并发性的影响。为了讨论的方便，我们把执行检索（SELECT）的客户端称为&amp;quot; 读取者&amp;quot;，把执行修改操作（DELETE、INSERT、REPLACE或UPDATE）的客户端称为&amp;quot;写入者&amp;quot;。 　　MySQL的默认的调度策略可用总结如下： 　　&amp;middot; 写入操作优先于读取操作。 　　&amp;middot; 对某张数据表的写入操作某一时刻只能发生一次，写入请求按照它们到达的次序来处理。 　　&amp;middot; 对某张数据表的多个读取操作可以同时地进行。 　　MyISAM和MEMORY存储引擎借助于数据表锁来实现这样的调度策略。当客户<br/><br/>1 投票人数 ]]></description>
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<item>
<title><![CDATA[InnoDB锁问题]]></title>
<link>http://www.yeeach.com/digg/story/455</link>
<comments>http://www.yeeach.com/digg/story/455</comments>
<pubDate>Sat, 05 Apr 2008 05:59:54 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/455</guid>
<description><![CDATA[InnoDB与MyISAM的最大不同有两点：一是支持事务（TRANSACTION）；二是采用了行级锁。行级锁与表级锁本来就有许多不同之处，另外，事务的引入也带来了一些新问题。下面我们先介绍一点背景知识，然后详细讨论InnoDB的锁问题。  背景知识  1．事务（Transaction）及其ACID属性  事务是由一组SQL语句组成的逻辑处理单元，事务具有以下4个属性，通常简称为事务的ACID属性。  l&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; 原子性（Atomicity）：事务是一个原子操作单元，其对数据的修改，要么全都执行，要么全都不执行。  <br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[An Unorthodox Approach to Database Design : The Coming of the Shard | High Scalability]]></title>
<link>http://www.yeeach.com/digg/story/399</link>
<comments>http://www.yeeach.com/digg/story/399</comments>
<pubDate>Sat, 22 Mar 2008 06:25:10 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/399</guid>
<description><![CDATA[ Once upon a time we scaled databases by buying ever bigger, faster, and more expensive machines. While this arrangement is great for big iron profit margins, it doesn't work so well for the bank accounts of our heroic system builders who need to scale well past what they can afford to spend on giant database servers. In a extraordinary two article series, Dathan Pattishall, explains his motivation for a revolutionary new database architecture--sharding--that he began thinking about even bef<br/><br/>1 投票人数 ]]></description>
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<item>
<title><![CDATA[DBA在系统设计、开发中的重要性]]></title>
<link>http://www.yeeach.com/digg/story/430</link>
<comments>http://www.yeeach.com/digg/story/430</comments>
<pubDate>Sat, 22 Mar 2008 06:22:02 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/430</guid>
<description><![CDATA[一、 现阶段DBA对系统性能及稳定性所做的调整工作目前DBA对系统性能的调整工作大致是这么几个方面： 1、 在硬件层面进行调优，这通常就是直接花钱，买设备、扩容。 2、 在DB层面进行调优，比如调整初始化参数，调整数据库物理结构。 3、 对应用的SQL进行优化，比如在数据库分析statspack，调整Top SQL。 4、 只有非常少数的，通常是对系统稳定要求较高的一些公司的应用，才会在新的应用上线前，让DBA对sql进行充分的审<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[Top free / open-source tools for MySQL Development / Administration]]></title>
<link>http://www.yeeach.com/digg/story/380</link>
<comments>http://www.yeeach.com/digg/story/380</comments>
<pubDate>Sat, 15 Mar 2008 05:00:23 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/380</guid>
<description><![CDATA[Administration, Adminstration, MySQL-DELETED, Tools 				Here is list of great tools for PHP/MySQL 1. phpMyAdmin  phpMy<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[A Few Common Performance Mistakes]]></title>
<link>http://www.yeeach.com/digg/story/387</link>
<comments>http://www.yeeach.com/digg/story/387</comments>
<pubDate>Sat, 15 Mar 2008 05:00:22 PDT</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/387</guid>
<description><![CDATA[As I run into the same mistake over and over again I am going to throw them out here in order to serve as a warning and a learning tool to others. Some of these may seem like I am beating a dead horse because you can find examples of these on other sites, in other blogs, or even in the manual. Despite the large amounts of data on the subjects these things still pop up. This is not a complete list, and this list is not in any order&amp;hellip; so please don&amp;rsquo;t disp<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[floating point: MySQL Scaling 101]]></title>
<link>http://www.yeeach.com/digg/story/336</link>
<comments>http://www.yeeach.com/digg/story/336</comments>
<pubDate>Thu, 28 Feb 2008 23:11:26 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/336</guid>
<description><![CDATA[ 		 			Several years ago, back when I was a consultant, I prepared this cool demo of Oracle's replication features for a project we were bidding on.&amp;nbsp; Through the magic of redo logs, writes to one server are propagated to the other server.&amp;nbsp; Oracle even had this cool little GUI that showed pending changes and other stats.&amp;nbsp; I was reminded of this episode while reading Cal Henderson's book on building scalable web sites (his slides were interesting so I figured I'd check his book <br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[优化MySQL性能的八大方法]]></title>
<link>http://www.yeeach.com/digg/story/318</link>
<comments>http://www.yeeach.com/digg/story/318</comments>
<pubDate>Sun, 17 Feb 2008 02:05:08 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/318</guid>
<description><![CDATA[ 			1、选取最适用的字段属性 MySQL可以很好的支持大数据量的存取，但是一般说来，数据库中的表越小，在它上面执行的查询也就会越快。因此，在创建表的时候，为了获得更好的 性能，我们可以将表中字段的宽度设得尽可能小。例如，在定义邮政编码这个字段时，如果将其设置为CHAR(255),显然给数据库增加了不必要的空间，甚 至使用VARCHAR这种类型也是多余的，因为CHAR(6)就可以很好的完成任务了。同样的，如果可以的话，我们应该使用MEDIUMINT而不是 BIGIN来定义整型字段。 另外一个提高效率的方法是在可能的情况下，应该尽量把字段设置为NOT NULL，这样在将来执行查询的时候，数据库不用去比较NULL值。 对于某些文本字段，例如&amp;ldquo;省份&amp;rdquo;或者&amp;ldquo;性别&amp;rdquo;，我们可以将它们定义为ENUM类型。因为在MySQL中，ENUM类型被当作数值型数据来处理，而数值型数据被处理起来的速度要比文本类型快得多。这样，我们又可以提高数据库的性能。 2、使用连接（JOIN）来代替子查询(Sub-<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[MySQL服务维护笔记 (笔记 by 车东)]]></title>
<link>http://www.yeeach.com/digg/story/317</link>
<comments>http://www.yeeach.com/digg/story/317</comments>
<pubDate>Sun, 17 Feb 2008 02:05:08 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/317</guid>
<description><![CDATA[                               内容摘要：使用MySQL服 务的一些经验，主要从以下几个方面考虑的MySQL服务规划设计。对于高负载站点来说PHP和MySQL运行在一起（或者说任何应用和数据库运行在一起的 规划）都是性能最大的瓶颈，这样的设计有如让人一手画圆一手画方，这样2个人的工作效率肯定不如让一个人专门画圆一个人专门画方效率高，让应用和数据库都 跑在一台高性能服务器上说不定还不如跑在2台普通服务器上快。  以下就是针对MySQL作为专门的数据库服务器的优化建议： MySQL服务的安装/配置的通用性；系统的升级和数据迁移方便性；备份和系统快速恢复；数据库应用的设计要点；一次应用优化实战；                                                                                                                <br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[Image storage: Database BLOB Vs. File system]]></title>
<link>http://www.yeeach.com/digg/story/286</link>
<comments>http://www.yeeach.com/digg/story/286</comments>
<pubDate>Mon, 11 Feb 2008 07:37:00 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/286</guid>
<description><![CDATA[This raises an age old question which will likely be debated for many years to come. Ultimately both methods of storage have their benefits and costs. Storing images on the file system has a marginally faster retrieval rate, thanks to web and proxy servers being good at what they do. Storing images in a database allows for all of your data to be central stored which is more portable, and easy to replicate. This solution would likely also be easier for taking a point-in-time bac<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[File system or BLOB?]]></title>
<link>http://www.yeeach.com/digg/story/294</link>
<comments>http://www.yeeach.com/digg/story/294</comments>
<pubDate>Mon, 11 Feb 2008 07:36:59 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/294</guid>
<description><![CDATA[File system or BLOB?   At Karora, we have a document management  engine that saves files in a &amp;quot;repository&amp;quot; (abstraction). The idea was that  you could choose between saving files on the file system, or in a BLOB column of  a database, when setting up the system.  I'm trying to figure out what the pros and cons each are. Here's what I've  though<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[Database Naming]]></title>
<link>http://www.yeeach.com/digg/story/293</link>
<comments>http://www.yeeach.com/digg/story/293</comments>
<pubDate>Mon, 11 Feb 2008 07:36:59 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/293</guid>
<description><![CDATA[Database developers have historically used a somewhat cryptic system              for naming database tables and fields.   Originally a result              of the limitations of database management systems (DBMS), these naming              schemes - or the lack thereof - have become adopted by convention              and tradition.  However, as database applications become more              complex, with more tables and larger teams of developers, and as developers            <br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[Essential Database Naming Conventions (and Style)]]></title>
<link>http://www.yeeach.com/digg/story/291</link>
<comments>http://www.yeeach.com/digg/story/291</comments>
<pubDate>Mon, 11 Feb 2008 07:36:59 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/291</guid>
<description><![CDATA[style  use lowercase characters 		eliminates question of proper case as well as errors related to case-sensitivity 		speeds typing rate and accuracy 		differentiates table and field names from uppercase SQL syntax 		 	separate words and prefixes with underlines, never use spaces 		promotes readability (e.g. book_name vs. bookname) 		avoid having to bracket names (e.g. [book name] or `book name`) 		offers gre<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[Naming Conventions in Database Design &lt; Database &lt; Bin-Co]]></title>
<link>http://www.yeeach.com/digg/story/290</link>
<comments>http://www.yeeach.com/digg/story/290</comments>
<pubDate>Mon, 11 Feb 2008 07:36:59 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/290</guid>
<description><![CDATA[Even though I am not a professional database administrator, I have designed a number of databases. One thing that always plagued me when doing this is the lack of a common convention that can be used to create the database design. So, I have decided to create one for myself.  You may not agree with all the rules given here - feel free to copy this list and create a set of rules for yourself. But once it is created, make sure that you st<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[DevCampus Database Naming Conventions - Jason Mauss' Blog Cabin]]></title>
<link>http://www.yeeach.com/digg/story/289</link>
<comments>http://www.yeeach.com/digg/story/289</comments>
<pubDate>Mon, 11 Feb 2008 07:36:59 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/289</guid>
<description><![CDATA[The main goal of adopting a naming convention for database objects is so that you and others can easily identify the type and purpose of all objects contained in the database. The information presented here serves as a guide for you to follow when naming your database objects. When reading these rules and guidelines remember that&amp;nbsp;consistent&amp;nbsp;naming&amp;nbsp;can be&amp;nbsp;the most important rule to follow. Keep in mind that&amp;nbsp; following&amp;nbsp;the guidelines as outlin<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[MySQL tuning 101]]></title>
<link>http://www.yeeach.com/digg/story/272</link>
<comments>http://www.yeeach.com/digg/story/272</comments>
<pubDate>Fri, 08 Feb 2008 04:17:33 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/272</guid>
<description><![CDATA[In my last post, I talked about how hard it was to find good resources for newbies to learn database tuning, especially with the very popular MySQL database &amp;mdash; the free or commercial version. This post will talk you through the basics of database tuning. Ready? here we go: 1) hardware is important. Ideally, your mySQL server will be on its own dedicated box. Sharing it with Apache and the rest of your application may be fine starting off, but eventually you&amp;rsquo;ll<br/><br/>1 投票人数 ]]></description>
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<title><![CDATA[MySQL优化经验]]></title>
<link>http://www.yeeach.com/digg/story/271</link>
<comments>http://www.yeeach.com/digg/story/271</comments>
<pubDate>Fri, 08 Feb 2008 04:17:33 PST</pubDate>
<dc:creator></dc:creator>
<category>技术-数据库</category>
<guid>http://www.yeeach.com/digg/story/271</guid>
<description><![CDATA[同时在线访问量继续增大 对于1G内存的服务器明显感觉到吃力严重时甚至每天都会死机 或者时不时的服务器卡一下 这个问题曾经困扰了我半个多月MySQL使用是很具伸缩性的算法，因此你通常能用很少的内存运行或给MySQL更多的被存以得到更好的性能。 安装好mysql后，配制文件应该在/usr/local/mysql/share/mysql目录中，配制文件有几个，有my- huge.cnf my-medium.cnf my-large.cnf my-small.cnf,不同的流量的网站和不同配制的服务器环境，当然需要有不同的配制文件了。 一般的情况下，my-medium.cnf这个配制文件就能满足我们的大多需要；一般我们会把配置文件拷贝到/etc/my.cnf 只需要修改这个配置文件就可以了，使用mysqladmin variables extended-status &amp;ndash;u root &amp;ndash;p 可以看到目前的参数，有３个配置参数是最重要的，即key_buffer_size,query_cache_size,table_cache。 <br/><br/>1 投票人数 ]]></description>
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