Thread:Project:Support desk/Fatal exception of type MWException after upgrading php and apache

After upgrading apache and php to latest version ( on ubuntu 12.04 ), I got this error "Fatal exception of type MWException"

detail:

[9ce78d3a] /wiki/index.php/%D8%B5%D9%81%D8%AD%D9%87%D9%94_%D8%A7%D8%B5%D9%84%DB%8C Exception from line 797 of /var/www/wiki/includes/db/Database.php: DatabaseBase::factory no viable database extension found for type 'mysql'

Backtrace:


 * 1) 0 /var/www/wiki/includes/db/LoadBalancer.php(730): DatabaseBase::factory(string, array)
 * 2) 1 /var/www/wiki/includes/db/LoadBalancer.php(606): LoadBalancer->reallyOpenConnection(array, boolean)
 * 3) 2 /var/www/wiki/includes/db/LoadBalancer.php(493): LoadBalancer->openConnection(integer, boolean)
 * 4) 3 /var/www/wiki/includes/GlobalFunctions.php(3649): LoadBalancer->getConnection(integer, array, boolean)
 * 5) 4 /var/www/wiki/includes/cache/LocalisationCache.php(1071): wfGetDB(integer)
 * 6) 5 /var/www/wiki/includes/cache/LocalisationCache.php(397): LCStore_DB->get(string, string)
 * 7) 6 /var/www/wiki/includes/cache/LocalisationCache.php(440): LocalisationCache->isExpired(string)
 * 8) 7 /var/www/wiki/includes/cache/LocalisationCache.php(324): LocalisationCache->initLanguage(string)
 * 9) 8 /var/www/wiki/includes/cache/LocalisationCache.php(259): LocalisationCache->loadItem(string, string)
 * 10) 9 /var/www/wiki/languages/Language.php(4122): LocalisationCache->getItem(string, string)
 * 11) 10 /var/www/wiki/languages/Language.php(238): Language::getFallbacksFor(string)
 * 12) 11 /var/www/wiki/languages/Language.php(197): Language::newFromCode(string)
 * 13) 12 /var/www/wiki/includes/Setup.php(537): Language::factory(string)
 * 14) 13 /var/www/wiki/includes/WebStart.php(153): require_once(string)
 * 15) 14 /var/www/wiki/index.php(46): require(string)
 * 16) 15 {main}