Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /var/www/html/includes/database/database.inc:2227
Stack trace:
#0 /var/www/html/includes/database/database.inc(2227): PDOStatement->execute(Array)
#1 /var/www/html/includes/database/database.inc(697): DatabaseStatementBase->execute(Array, Array)
#2 /var/www/html/includes/database/database.inc(2406): DatabaseConnection->query('SELECT expire, ...', Array, Array)
#3 /var/www/html/includes/lock.inc(167): db_query('SELECT expire, ...', Array)
#4 /var/www/html/includes/lock.inc(146): lock_may_be_available('theme_registry:...')
#5 /var/www/html/includes/theme.inc(449): lock_acquire('theme_registry:...')
#6 /var/www/html/includes/bootstrap.inc(460): ThemeRegistry->set(Array)
#7 [internal function]: DrupalCacheArray->__destruct()
#8 {main}
thrown in /var/www/html/includes/database/database.inc on line 2227