Mysql读写分离--PHP实现_PHP_编程开发_程序员俱乐部

本代码是从uchome的代码修改的，是因为要解决uchome的效率而处理的。
这个思维其实很久就有了，只是一直没有去做，相信也有人有同样的想法，如果有类似的，那真的希望提出相关的建议。
封装的方式比较简单，增加了只读数据库连接的接口扩展，不使用只读数据库也不影响原代码使用。
有待以后不断完善。。

为了方便，试试建立了google的一个项目：
http://code.google.com/p/mysql-rw-php/

希望给有需要的朋友带来帮助。

PHP实现的Mysql读写分离

主要特性：

1. 简单的读写分离
2. 一个主数据库，可以添加更多的只读数据库
3. 读写分离但不用担心某些特性不支持
4. 缺点：同时连接两个数据库

英文比较烂，也写几个字吧

php code for mysql read/write split
feature:
simply rw split?
one master,can add more slaves?
support all mysql feature?
link to the master and slave at the same time

PHP代码：

mysql_rw_php.class.php

mono; font-size: 12px; line-height: 18px; background-color: #ddedfb; margin: 5px; padding: 5px; width: 480px; border: 1px solid #0099cc; display: block;"><?php
/****************************************
*** mysql-rw-php version 0.1 @ 2009-4-16
*** code by hqlulu#gmail.com
***?http://www.aslibra.com
***?http://code.google.com/p/mysql-rw-php/
*** code modify from class_mysql.php (uchome)
****************************************/
class mysql_rw_php {
? //查询个数
? var $querynum = 0;
? //当前操作的数据库连接
? var $link = null;
? //字符集
? var $charset;
? //当前数据库
? var $cur_db = '';
? //是否存在有效的只读数据库连接
? var $ro_exist = false;
? //只读数据库连接
? var $link_ro = null;
? //读写数据库连接
? var $link_rw = null;
? function mysql_rw_php(){
? }
? function connect($dbhost, $dbuser, $dbpw, $dbname = '', $pconnect = 0, $halt = TRUE) {
??? if($pconnect) {
????? if(!$this->link = @mysql_pconnect($dbhost, $dbuser, $dbpw)) {
??????? $halt && $this->halt('Can not connect to MySQL server');
????? }
??? } else {
????? if(!$this->link = @mysql_connect($dbhost, $dbuser, $dbpw)) {
??????? $halt && $this->halt('Can not connect to MySQL server');
????? }
??? }
????
??? //只读连接失败
??? if(!$this->link && !$halt) return false;
????
??? //未初始化rw时，第一个连接作为rw
??? if($this->link_rw == null)
????? $this->link_rw = $this->link;
??? if($this->version() > '4.1') {
????? if($this->charset) {
??????? @mysql_query("SET character_set_connection=$this->charset, character_set_results=$this->charset, character_set_client=binary", $this->link);
????? }
????? if($this->version() > '5.0.1') {
??????? @mysql_query("SET sql_mode=''", $this->link);
????? }
??? }
??? if($dbname) {
????? $this->select_db($dbname);
??? }
? }
? //连接一个只读的mysql数据库
? function connect_ro($dbhost, $dbuser, $dbpw, $dbname = '', $pconnect = 0){
??? if($this->link_rw == null)
????? $this->link_rw = $this->link;
??? $this->link = null;
??? //不产生halt错误
??? $this->connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect, false);
??? if($this->link){
????? //连接成功
????? //echo "link ro sussess!<br>";
????? $this->ro_exist = true;
????? $this->link_ro = $this->link;
????? if($this->cur_db){
??????? //如果已经选择过数据库则需要操作一次
??????? @mysql_select_db($this->cur_db, $this->link_ro);
????? }
??? }else{
????? //连接失败
????? //echo "link ro failed!<br>";
????? $this->link = &$this->link_rw;
??? }
? }
? //设置一系列只读数据库并且连接其中一个
? function set_ro_list($ro_list){
??? if(is_array($ro_list)){
????? //随机选择其中一个
????? $link_ro = $ro_list[array_rand($ro_list)];
????? $this->connect_ro($link_ro['dbhost'], $link_ro['dbuser'], $link_ro['dbpw']);
??? }
? }
? function select_db($dbname) {
??? //同时操作两个数据库连接
??? $this->cur_db = $dbname;
??? if($this->ro_exist){
????? @mysql_select_db($dbname, $this->link_ro);
??? }
??? return @mysql_select_db($dbname, $this->link_rw);
? }
? function fetch_array($query, $result_type = MYSQL_ASSOC) {
??? return mysql_fetch_array($query, $result_type);
? }
? function fetch_one_array($sql, $type = '') {
??? $qr = $this->query($sql, $type);
??? return $this->fetch_array($qr);
? }
? function query($sql, $type = '') {
??? $this->link = &$this->link_rw;
??? //判断是否select语句
??? if($this->ro_exist && preg_match ("/^(\s*)select/i", $sql)){
????? $this->link = &$this->link_ro;
??? }
??? $func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ?
????? 'mysql_unbuffered_query' : 'mysql_query';
??? if(!($query = $func($sql, $this->link)) && $type != 'SILENT') {
????? $this->halt('MySQL Query Error', $sql);
??? }
??? $this->querynum++;
??? return $query;
? }
? function affected_rows() {
??? return mysql_affected_rows($this->link);
? }
? function error() {
??? return (($this->link) ? mysql_error($this->link) : mysql_error());
? }
? function errno() {
??? return intval(($this->link) ? mysql_errno($this->link) : mysql_errno());
? }
? function result($query, $row) {
??? $query = @mysql_result($query, $row);
??? return $query;
? }
? function num_rows($query) {
??? $query = mysql_num_rows($query);
??? return $query;
? }
? function num_fields($query) {
??? return mysql_num_fields($query);
? }
? function free_result($query) {
??? return mysql_free_result($query);
? }
? function insert_id() {
??? return ($id = mysql_insert_id($this->link)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
? }
? function fetch_row($query) {
??? $query = mysql_fetch_row($query);
??? return $query;
? }
? function fetch_fields($query) {
??? return mysql_fetch_field($query);
? }
? function version() {
??? return mysql_get_server_info($this->link);
? }
? function close() {
??? return mysql_close($this->link);
? }
? function halt($message = '', $sql = '') {
??? $dberror = $this->error();
??? $dberrno = $this->errno();
??? echo "<div style=\"position:absolute;font-size:11px;font-family:verdana,arial;background:#EBEBEB;padding:0.5em;\">
??????? <b>MySQL Error</b><br>
??????? <b>Message</b>: $message<br>
??????? <b>SQL</b>: $sql<br>
??????? <b>Error</b>: $dberror<br>
??????? <b>Errno.</b>: $dberrno<br>
??????? </div>";
??? exit();
? }
}
?>

example.php

<?php
/****************************************
*** mysql-rw-php version 0.1 @ 2009-4-16
*** code by hqlulu#gmail.com
***?http://www.aslibra.com
***?http://code.google.com/p/mysql-rw-php/
*** code modify from class_mysql.php (uchome)
****************************************/
require_once('mysql_rw_php.class.php');
//rw info
$db_rw = array(
? 'dbhost'=>'www.aslibra.com',
? 'dbuser'=>'aslibra',
? 'dbpw'=>'www.aslibra.com',
? 'dbname'=>'test'
);
$db_ro = array(
? array(
??? 'dbhost'=>'www.aslibra.com:4306',
??? 'dbuser'=>'aslibra',
??? 'dbpw'=>'www.aslibra.com'
? )
);
$DB = new mysql_rw_php;
//connect Master
$DB->connect($db_rw[dbhost], $db_rw[dbuser], $db_rw[dbpw], $db_rw[dbname]);
//Method 1: connect one server
$DB->connect_ro($db_ro[0][dbhost], $db_ro[0][dbuser], $db_ro[0][dbpw]);
//Method 2: connect one server from a list by rand
$DB->set_ro_list($db_ro);
//send to rw
$sql = "insert into a set a='test'";
$DB->query($sql);
//send to ro
$sql = "select * from a";
$qr = $DB->query($sql);
while($row = $DB->fetch_array($qr)){
? echo $row[a];
}
?>