来自： http://blog.csdn.net/21aspnet/article/details/50774684
SQL Relay按照其官网http://sqlrelay.sourceforge.net/index.html上所说是：A powerful database connection management solution.
翻译为中文也就是说SQL Relay是一个开源的数据库池连接代理服务器。
目前SQL Relay支持的数据库很多：
SQL Relay supports Oracle, MySQL, PostgreSQL, SAP/Sybase, IBM DB2, Informix, Firebird and SQLite databases directly, using the native client API's for those databases.
Support is provided for Microsoft SQL Server via the FreeTDS API.
支持的API也是非常丰富的
Guides: C++, C, C#, Perl, PHP, Python, Ruby, Java, TCL, Erlang, node.js
References: C++, C, C#, Perl, PHP, Python, Ruby, Java, TCL, node.js,
本人讲述怎么在Linux+PHP+FreeDTS环境使用连接池，其实PHP->SQL Relay->FreeDTS->数据库 这样的架构。
下面说安装使用
1.先安装rudiments
建议尽量安装新版，旧版可能会报错需要解决。
# wget http://sourceforge.net/projects/rudiments/files/rudiments/0.28.2/rudiments-0.28.2.tar.gz/download
# tar xvzf rudiments-0.54.tar.gz
# cd rudiments-0.54
# ./configure --prefix=/usr/local/rudiments
# make && make install
2.再安装sqlrelay
# wget https://sourceforge.net/projects/sqlrelay/files/sqlrelay/0.64/sqlrelay-0.64.tar.gz/download
# tar vxzf sqlrelay-0.64.tar.gz
# cd sqlrelay-0.64
# ./configure --prefix=/usr/local/sqlrelay --with-rudiments-prefix=/usr/local/rudiments --with-freetds-prefix=/usr/local/freetds --with-php-prefix=/usr/local/php
# make && make install
3.修改php配置文件
# vim /usr/local/php/lib/php.ini
增加扩展
extension ="sql_relay.so"
4.修改freeDTS配置
关于freeDTS的安装参考此文：http://blog.csdn.net/unix21/article/details/47449901
修改FreeTDS的配置文件freetds.conf
# vim /usr/local/freetds/etc/freetds.conf
加入以下内容
[msdetest]host = 192.168.1.1port =1433tds version = 7.0client charset = UTF-8
5.修改SQL Relay的配置文件
# cd /usr/local/sqlrelay/etc/
# cp sqlrelay.conf.example sqlrelay.conf
# vim sqlrelay.conf
整个配置非常好理解
<?xml version="1.0"?><!DOCTYPE instances SYSTEM "sqlrelay.dtd"><instances><instance id="msdetest" port="9001" socket="/tmp/msdetest.socket" dbase="freetds" connections="10" maxconnections="50" maxqueuelength="0" growby="1" ttl="60" endofsession="commit" sessiontimeout="5" runasuser="nobody" runasgroup="nobody" cursors="5" authtier="listener" handoff="pass"><users><user user="admin" password="admin"/></users><connections><connection connectionid="msdetest" string="server=msde;db=test;user=admin;password=admin;" metric="1"/></connections></instance></instances>
# export PATH=$PATH:/usr/local/sqlrelay/bin
启动：
# sqlr-start -id msde
上图是成功启动，如果配置错误会提示数据库连不上之类的。
SQL工具
# sqlrsh -id msde
7.php使用连接池
<?php$con=sqlrcon_alloc("msdetest",9001,"/tmp/msdetest.socket","admin","admin",0,1);$cur=sqlrcur_alloc($con);sqlrcur_sendQuery($cur,"SELECT top 10 * FROM test order by id desc");for ($row=0; $row<sqlrcur_rowCount($cur); $row++) {for ($col=0; $col<sqlrcur_colCount($cur); $col++) {echo sqlrcur_getField($cur,$row,$col);echo ",";}echo "<br>\n";}sqlrcur_free($cur);sqlrcon_free($con);?>
SQL Relay的PHP函数API
http://sqlrelay.sourceforge.net/sqlrelay/programming/php.html
参考：http://www.cnblogs.com/zhangjun516/archive/2013/03/12/2955162.html
