Mine

A database error has occurred
Query: BEGIN
Function: Database::begin
Error: 2002 Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (localhost)

Backtrace:

    * GlobalFunctions.php line 451 calls wfBacktrace()
    * Database.php line 398 calls wfDebugDieBacktrace()
    * Database.php line 348 calls Database::reportQueryError()
    * Database.php line 1440 calls Database::query()
    * Database.php line 1410 calls Database::immediateBegin()
    * Database.php line 322 calls Database::begin()
    * Database.php line 255 calls Database::query()
    * Database.php line 175 calls Database::open()
    * LoadBalancer.php line 429 calls Database::Database()
    * LoadBalancer.php line 379 calls LoadBalancer::reallyOpenConnection()
    * LoadBalancer.php line 594 calls LoadBalancer::openConnection()
    * LoadBalancer.php line 118 calls LoadBalancer::getLagTimes()
    * LoadBalancer.php line 179 calls LoadBalancer::getRandomNonLagged()
    * LoadBalancer.php line 344 calls LoadBalancer::getReaderIndex()
    * DatabaseFunctions.php line 52 calls LoadBalancer::getConnection()
    * User.php line 675 calls wfGetDB()
    * User.php line 625 calls User::loadFromDatabase()
    * Setup.php line 212 calls User::loadFromSession()
    * index.php line 63 calls require_once()