php Unable to load dynamic library dll

今天测试apache+php+postgresql，发现apache给出warning:

PHP Warning: PHP Startup: Unable to load dynamic library ‘C:\php5\ext\php_pgsql.dll’ – 找不到指定的模块。 in Unknown on line 0 PHP Warning: Cannot load module ‘pdo_mysql’ because required module ‘pdo’ is not loaded in Unknown on line

但是其他模块儿都可以默认路径加载进来，而且php/ext/目录下确实有php_pgsql.dll，但就是加载不到，百度、google了一把发现只需要把php安装目录下的“libpq.dll” 拷贝到%sytem%/system32/ 目录下即可重启apache解决.