Can't connect to local MySQL server error on Magento

Question

My website uses Magento and is hosted on Godaddy. It was working fine till yesterday but today, it is showing the following error :

There has been an error processing your request
SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

Trace:
#0 /home/greenveggy/public_html/lib/Zend/Db/Adapter/Pdo/Mysql.php(109): Zend_Db_Adapter_Pdo_Abstract->_connect()
#1 /home/greenveggy/public_html/lib/Varien/Db/Adapter/Pdo/Mysql.php(320): Zend_Db_Adapter_Pdo_Mysql->_connect()
#2 /home/greenveggy/public_html/lib/Zend/Db/Adapter/Abstract.php(460): Varien_Db_Adapter_Pdo_Mysql->_connect()
#3 /home/greenveggy/public_html/lib/Zend/Db/Adapter/Pdo/Abstract.php(238): Zend_Db_Adapter_Abstract->query('SET NAMES utf8', Array)
#4 /home/greenveggy/public_html/lib/Varien/Db/Adapter/Pdo/Mysql.php(428): Zend_Db_Adapter_Pdo_Abstract->query('SET NAMES utf8', Array)
#5 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource.php(169): Varien_Db_Adapter_Pdo_Mysql->query('SET NAMES utf8')
#6 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource.php(110): Mage_Core_Model_Resource->_newConnection('pdo_mysql',    Object(Mage_Core_Model_Config_Element))
#7 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(320): Mage_Core_Model_Resource->getConnection('core_write')
#8 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(350): Mage_Core_Model_Resource_Db_Abstract->_getConnection('write')
#9 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(335): Mage_Core_Model_Resource_Db_Abstract->_getWriteAdapter()
#10 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(360): Mage_Core_Model_Resource_Db_Abstract->_getReadAdapter()
#11 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Resource/Db/Collection/Abstract.php(134): Mage_Core_Model_Resource_Db_Abstract->getReadConnection()
#12 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Config.php(1348): Mage_Core_Model_Resource_Db_Collection_Abstract->__construct(Object(Mage_Core_Model_Resource_Website))
#13 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Config.php(1380): Mage_Core_Model_Config->getModelInstance('core_resource/w...', Object(Mage_Core_Model_Resource_Website))
#14 /home/greenveggy/public_html/app/Mage.php(491): Mage_Core_Model_Config->getResourceModelInstance('core/website_co...', Object(Mage_Core_Model_Resource_Website))
#15 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Abstract.php(208): Mage::getResourceModel('core/website_co...', Object(Mage_Core_Model_Resource_Website))
#16 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/Abstract.php(213): Mage_Core_Model_Abstract->getResourceCollection()
#17 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/App.php(608): Mage_Core_Model_Abstract->getCollection()
#18 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/App.php(466): Mage_Core_Model_App->_initStores()
#19 /home/greenveggy/public_html/app/code/core/Mage/Core/Model/App.php(349): Mage_Core_Model_App->_initCurrentStore('', 'store')
#20 /home/greenveggy/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#21 /home/greenveggy/public_html/index.php(87): Mage::run('', 'store')
#22 {main}

How do i resolve this ?

Answer 1

you can use the tool n98-magerun.phar ( link ) with task sys:check to test yout db-connection

• you have to copy the file to path /home/greenveggy/public_html/ and make it executable
• then cd to this path and execute ./n98-magerun.phar sys:check

if the connection fails check your properties in /home/greenveggy/public_html/app/etc/local.xml

Answer 2

Pressing the "check" button for the Database solved the problem. Site is functional again. Can anyone explain what just happened?