MySQL基础知识

Starting MySQL 4.1, MySQL had support for what is called derived tables, inline views or basically subselects in the from clause.
In MySQL 5.0 support for views was added.

从MySQL 4.1开始，它已经支持派生表、联机视图或者基本的FROM从句的子查询。

These features are quite related to each other but how do they compare in terms of performance ?

这些特性之间彼此相关，但是它们之间的性能比较如何呢？

Derived Tables in MySQL 5.0 seems to have different implementation from views, even though I would expect code base to be merged as it is quite the same task in terms of query optimization.

If someone asks me about MySQL Backup advice my first question would be if they have LVM installed or have some systems with similar features set for other operation systems. Veritas File System can do it for Solaris. Most SAN systems would work as well.

如果有人问我关于MySQL备份的建议，我会先问操作系统是否安装了LVM或者其他相似功能的软件。Solaris下的Veritas文件系统也可以做到同样的功能。大多数SAN系统也可以。

What is really needed is ability to create atomic snapshot of the volume, which can be later mounted same as original file system

MySQL Cluster 是MySQL适合于分布式计算环境的高实用、高冗余版本。它采用了NDB Cluster 存储引擎，允许在1个 Cluster 中运行多个MySQL服务器。在MyQL 5.0及以上的二进制版本中、以及与最新的Linux版本兼容的RPM中提供了该存储引擎。（注意，要想获得MySQL Cluster 的功能，必须安装 mysql-server 和 mysql-max RPM）。
目前能够运行MySQL Cluster 的操作系统有Linux、Mac OS X和Solaris（一些用户通报成功地在FreeBSD上运行了MySQL Cluster ，但MySQL AB公司尚未正式支持该特性）。
一、MySQL Cluster概述

Descending indexing and loose index scan
降序索引和减轻索引扫描

Comments to my previous posts, especially this one by Gokhan inspired me to write a bit about descending indexes and about loose index scan, or what Gokhan calls “better range” support. None of these are actially related to Innodb tables in general - these are features MySQL should get for all storage engines at some point.

由于存储过程中定义参数时，无法定义其字符集，因此调用存储过程的时候，会默认读取全局变量character_set_server，而且还是只读取mysqld启动时该全局变量的值作为存储过程中默认的传输字符集。因此，如果数据表/字段使用系统默认的字符集(比如latin1)的话，调用存储过程更新一些非英文的字符串字段时，就不会发生问题；但是，如果数据表/字段的字符集不是系统默认的字符集(比如默认是latin1，数据表使用的是utf8)，就会出现问题了。解决办法是：在my.cnf(windows下是my.ini)，增加一行：

default-character-set=utf8

或者

• 用mysql内置函数转换ip地址和数字
  利用两个内置函数
  inet_aton:将ip地址转换成数字型
  inet_ntoa:将数字型转换成ip地址

• 充分利用mysql内置的format函数
  尤其是在处理字符格式的时候,例如将12345转换成12,345这样的,只要用:format(12345,0)即可,如果用format(12345,2)则显示的是12,345.00了...

• 利用mysql的内置函数处理时间戳问题
  eg : select FROM_UNIXTIME(UNIX_TIMESTAMP(),'%Y %D %M %h:%i:%s %x');
  结果: 2004 3rd August 03:35:48 2004

• 利用mysql_convert_table_format转换表类型
  需要DBI和DBD的mysql相关模块支持才能用,例子:
  mysql_convert_table_format --user=root --password='xx' --type=myisam test yejr

come from:http://www.mysql.com

A few years ago, I wrote an article entitled "The Foundation of Excellent Performance" (still available at http://www.tdan.com/i016fe03.htm) where I argued against the notion that SQL code was the number one contributor to performance in a database-driven system. Instead, I stated in the article that I firmly believed how good physical database design was far and away the leading component of superior database performance. In addition, I showed that Oracle's own research illustrated how poor design was the main culprit behind database downtime (planned or unplanned). In the years since then, I've not changed my stance and still think that any DBA who wants a high-performance database has got to invest in intelligent and savvy physical design to produce the kind of response times that make end users smile instead of scream.

译者：叶金荣（Email:），来源：MySQL手册版本 5.0.1-alpha，转载请注明译者，并且不能用于商业用途，违者必究。

Q: 如何安装LAMP(Linux+Apache+MySQL+PHP)
A:[url]http://www.freelamp.com/1003235699/index_html[/url]

Q: 如何使用rpm方式安装mysql
A:首先下载合适的rpm包，例如下载了文件 MySQL-5.0.15-0.i386.rpm
用一下方法安装：
#rpm -ivhU MySQL-5.0.15-0.i386.rpm
通常情况下，安装完这个rpm包后，只具备有mysqld服务功能，其它相关的client程序和开发包还需要另外安装
#rpm -ivhU MySQL-devel-5.0.15-0.i386.rpm
#rpm -ivhU MySQL-client-5.0.15-0.i386.rpm

Q: 如何安装已经编译好了的mysql二进制包