Magento 1.9 - There has been an error processing your request

Question

It's printing an error message about some files, but I couldn't find the files on my server in the directory of /run.

SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

Trace:
# 0 /var/www/html/lib/Zend/Db/Adapter/Pdo/Mysql.php(111): Zend_Db_Adapter_Pdo_Abstract->_connect()
# 1 /var/www/html/lib/Varien/Db/Adapter/Pdo/Mysql.php(396): Zend_Db_Adapter_Pdo_Mysql->_connect()
# 2 /var/www/html/lib/Zend/Db/Adapter/Abstract.php(460): Varien_Db_Adapter_Pdo_Mysql->_connect()
# 3 /var/www/html/lib/Zend/Db/Adapter/Pdo/Abstract.php(238): Zend_Db_Adapter_Abstract->query('SET NAMES utf8', Array)
# 4 /var/www/html/lib/Varien/Db/Adapter/Pdo/Mysql.php(504): Zend_Db_Adapter_Pdo_Abstract->query('SET NAMES utf8', Array)
# 5 /var/www/html/app/code/core/Mage/Core/Model/Resource.php(179): Varien_Db_Adapter_Pdo_Mysql->query('SET NAMES utf8')
# 6 /var/www/html/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/app/code/core/Mage/Core/Model/Resource/Setup.php(141): Mage_Core_Model_Resource->getConnection('core_setup')
# 8 /var/www/html/app/code/core/Mage/Core/Model/Resource/Setup.php(234): Mage_Core_Model_Resource_Setup->__construct('core_setup')
# 9 /var/www/html/app/code/core/Mage/Core/Model/App.php(428): Mage_Core_Model_Resource_Setup::applyAllUpdates()
# 10 /var/www/html/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Model_App->_initModules()
# 11 /var/www/html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
# 12 /var/www/html/index.php(83): Mage::run('', 'store')
# 13 {main}

Answer 1

Finally resolved below are the steps to do:

Step #1 First can create the mysqld/ directory in /var/run/: sudo mkdir -p /var/run/mysqld/

Step #2 Then create a mysqld.pid file: sudo touch /var/run/mysqld/mysqld.pid

Step #3 Create a mysqld.sock file: sudo touch /var/run/mysqld/mysqld.sock

Step #4 Then you have to change the ownership of the directory and files to mysql:mysql like the below: sudo chown mysql:mysql -R /var/run/mysqld

Step #5 And finally restart the MySQL: sudo service mysql restart

Step #6 That’s it you did all done well, MySQL will be able to create the mysqld.pid and mysqld.sock files in the root directory. Great work & Good luck!