这是一次非常奇怪的错误，正在测试站点，突然间就直接报了以下错误

SQLSTATE[HY000] [1045] Access denied for user 'root'@'localhost' (using password: YES)


#0 /var/www/html/test/lib/Zend/Db/Adapter/Pdo/Mysql.php(111): Zend_Db_Adapter_Pdo_Abstract->_connect()
#1 /var/www/html/test/lib/Varien/Db/Adapter/Pdo/Mysql.php(396): Zend_Db_Adapter_Pdo_Mysql->_connect()
#2 /var/www/html/test/lib/Zend/Db/Adapter/Abstract.php(460): Varien_Db_Adapter_Pdo_Mysql->_connect()
#3 /var/www/html/test/lib/Zend/Db/Adapter/Pdo/Abstract.php(238): Zend_Db_Adapter_Abstract->query('SET NAMES utf8', Array)
#4 /var/www/html/test/lib/Varien/Db/Adapter/Pdo/Mysql.php(504): Zend_Db_Adapter_Pdo_Abstract->query('SET NAMES utf8', Array)
#5 /var/www/html/test/app/code/core/Mage/Core/Model/Resource.php(179): Varien_Db_Adapter_Pdo_Mysql->query('SET NAMES utf8')
#6 /var/www/html/test/app/code/core/Mage/Core/Model/Resource.php(110): Mage_Core_Model_Resource->_newConnection('pdo_mysql', Object(Mage_Core_Model_Config_Element))
#7 /var/www/html/test/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(320): Mage_Core_Model_Resource->getConnection('core_write')
#8 /var/www/html/test/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(350): Mage_Core_Model_Resource_Db_Abstract->_getConnection('write')
#9 /var/www/html/test/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(335): Mage_Core_Model_Resource_Db_Abstract->_getWriteAdapter()
#10 /var/www/html/test/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(360): Mage_Core_Model_Resource_Db_Abstract->_getReadAdapter()
#11 /var/www/html/test/app/code/core/Mage/Core/Model/Resource/Db/Collection/Abstract.php(134): Mage_Core_Model_Resource_Db_Abstract->getReadConnection()
#12 /var/www/html/test/app/code/core/Mage/Core/Model/Config.php(1354): Mage_Core_Model_Resource_Db_Collection_Abstract->__construct(Object(Mage_Core_Model_Resource_Website))
#13 /var/www/html/test/app/code/core/Mage/Core/Model/Config.php(1386): Mage_Core_Model_Config->getModelInstance('core_resource/w...', Object(Mage_Core_Model_Resource_Website))
#14 /var/www/html/test/app/Mage.php(491): Mage_Core_Model_Config->getResourceModelInstance('core/website_co...', Object(Mage_Core_Model_Resource_Website))
#15 /var/www/html/test/app/code/core/Mage/Core/Model/Abstract.php(208): Mage::getResourceModel('core/website_co...', Object(Mage_Core_Model_Resource_Website))
#16 /var/www/html/test/app/code/core/Mage/Core/Model/Abstract.php(213): Mage_Core_Model_Abstract->getResourceCollection()
#17 /var/www/html/test/app/code/core/Mage/Core/Model/App.php(619): Mage_Core_Model_Abstract->getCollection()
#18 /var/www/html/test/app/code/core/Mage/Core/Model/App.php(477): Mage_Core_Model_App->_initStores()
#19 /var/www/html/test/app/code/core/Mage/Core/Model/App.php(360): Mage_Core_Model_App->_initCurrentStore('', 'store')
#20 /var/www/html/test/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#21 /var/www/html/test/index.php(85): Mage::run('', 'store')
#22 {main}

怎么无法连接数据库了？都没动过配置呀！尝试重启mysql，命令行进入数据库都是正常，唯独从浏览器上访问页面报了这错！

真是奇葩，我也没做过什么处理呀？只是新搞的开发环境，media的文件给了个777权限，而var下也给了一下777权限而已

难不成是缓存的原因？于是试了一下删除var下的文件，操作如下：

rm -rf var/cache/*
rm -rf var/session/*
rm -rf var/log/*

结论：有可能是目录缓存原因，新的环境是在没有关闭后台缓存的时候，进行的代码复制及数据库复制导入操作（新环境的mysql是不一样的），配置开发环境时，进后台关了缓存，但var目录没处理权限，发现产品详情页面不能访问报了media下文件错误时，给了777权限时，顺便给了var权限，导致程序能直接原来的缓存数据，导致使用了错误的配置信息