MySql優化之二三事

sql語句之優劣

better way

select @maxid :=max(nid) from node;

select * from node_revisions where nid = @maxid

better way (if either of nid and created is not index)

select * from node where nid > 10

union

select * from node where create > 1209793459

better way (using subquery is not a good choice in common)

select n.* from node n left join term_node t on t.nid = n.nid where tid < 10

group by之優化

select count(nid) from node group by vid order by null

explain:

create index之優化

when you create index on varchar or char column, partial index is better than all index, especially in large column:

create index name_index on users (name (10)); it will create index only the first 10 characters.

mysql server configuration

add configuration for mysql section

[mysqld]

skip-name-resolve #don』t resolve hostnames

compile mysql on linuxconfig.mysql.sh

#!/bin/bash

exe=configure

$exe --prefix=/opt/mysql --localstatedir=/opt/mysql/data --with-mysqld-user=mysql --sysconfdir=/opt/mysql/etc --with-unix-socket-path=/opt/mysql/temp/mysql.sock --with-tcp-port=3307 --with-charset=utf8 --with-extra-charsets=all --with-mysqld-ldflags=-all-static --with-client-ldflags=-all-static --enable-assembler --enable-thread-safe-client --with-pthread --without-debug --without--isam #configure的相關引數： #--prefix=/home/mysql/ /指定安裝目錄 #--without-debug /去除debug模式 #--with-extra-charsets=gbk,gb2312,utf8 /新增gbk,gb2312,utf8中文字元支援 #--with-pthread /強制使用pthread庫(posix執行緒庫) #--enable-assembler /使用一些字元函式的彙編版本 #--enable-thread-safe-client /以執行緒方式編譯客戶端 #--with-client-ldflags=-all-static /以純靜態方式編譯客戶端 #--with-mysqld-ldflags=-all-static /以純靜態方式編譯服務端 #--without-isam /去掉isam表型別支援，現在很少用了，isam表是一種依賴平台的表 #--without-innodb /去掉innodb表支援，innodb是一種支援事務處理的表，適合企業級應用

problems in mysql

遠端無法訪問 1. mysql>grant all privileges on *.* to 'user'@'%' identified by "1234";

允許xoops_root使用者可以從任意機器上登入mysql。

$sudo gedit /etc/mysql/my.cnf

老的版本中

>skip-networking => # skip-networking

新的版本中

>bind-address=127.0.0.1 => bind-address= 你機器的ip

127.0.0.1知允許本地訪問

MySql優化之二三事

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今日二三事

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MySql優化之二三事

埠二三事

今日二三事

生活二三事

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