Try waiting a few minutes and reloading.
(Cannot access the database)
Backtrace:
#0 /var/www/public_html/ru/includes/libs/rdbms/loadbalancer/LoadBalancer.php(897): Database->reportConnectionError('Unknown error (...')
#1 /var/www/public_html/ru/includes/libs/rdbms/loadbalancer/LoadBalancer.php(572): LoadBalancer->reportConnectionError()
#2 /var/www/public_html/ru/includes/GlobalFunctions.php(3075): LoadBalancer->getConnection(-1, Array, false)
#3 /var/www/public_html/ru/includes/Revision.php(322): wfGetDB(-1)
#4 /var/www/public_html/ru/includes/Revision.php(111): Revision::newFromConds(Array, 0)
#5 /var/www/public_html/ru/includes/MediaWiki.php(105): Revision::newFromId(91995)
#6 /var/www/public_html/ru/includes/MediaWiki.php(136): MediaWiki->parseTitle()
#7 /var/www/public_html/ru/includes/MediaWiki.php(766): MediaWiki->getTitle()
#8 /var/www/public_html/ru/includes/MediaWiki.php(512): MediaWiki->main()
#9 /var/www/public_html/ru/index.php(43): MediaWiki->run()
#10 {main}