mysql-proxy \–proxy-backend-addresses=narcissus:3306 \–proxy-backend-addresses=nostromo:3306
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3、数据库读写分离，192.168.18.110负责写入，192.168.18.107负责读取数据，当然也可以再增加读取数据的服务器。
mysql-proxy \–proxy-backend-addresses=192.168.18.110:3306 \–proxy-read-only-backend-addresses=192.168.18.107:3306
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这种方式并不是读写分离。mysql-proxy不能区分哪些是发往从服务器的，还需要自己用脚本控制，见第四种方式。
4、 lua 脚本能很好的控制连接和分布, 以及查询及返回的结果集.使用lua脚本时，必须使用 –proxy-lua-script 指定脚本的名称。直到产生连接时才会读取脚本，也就是修改脚本后不用重新启动服务。mysql-proxy –proxy-lua-script=rw-splitting.lua –proxy-backend-addresses=192.168.18.110:3306 –proxy-read-only-backend-addresses=192.168.18.107:3306
注意问题：1、proxy的读写分离机制是先把最初的几条查询发到master上建立连接，当发送到master上的查询数超过连接池的最小值时开始把查询
2、last_insert_id不能发送到主服务器上， 226 行修改为下面的就可以了elseif not is_insert_id and token.token_name == “tk_function” then
3、使用默认的rw-splitting.lua时，会提示找不到proxy-command，我把mysql-proxy的路径设置为系统路径，然后在 share目录下运行就一切ok了，在运行中输入cmd，然后cd c:\tools\mysql-proxy\share。
4、字符乱码通过proxy连上数据库之后，查到的字符串始终是乱码，即便手工执行了set names ‘utf8′也没有效果。解决办法，mysql server必须设置
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!
; $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!
; $this->link = &$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 mysql error
message: $message
sql: $sql
error: $dberror
errno.: $dberrno
; exit(); } }?>
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调用示例：
'bbs.it-home.org', 'dbuser'=>'jbxue', 'dbpw'=>'bbs.it-home.org', 'dbname'=>'test' ); $db_ro = array( array( 'dbhost'=>'bbs.it-home.org:4306', 'dbuser'=>'jbxue', 'dbpw'=>'bbs.it-home.org' ) ); $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]; } ?>
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