MediaWiki internal error.

Original exception: exception 'DBQueryError' with message 'A database error has occurred
Query: SELECT page_id, page_namespace, page_title, page_is_redirect, page_len FROM `page` WHERE (page_namespace=0 AND page_title IN('Elizabeth_Reed', 'Fia_Kareman', 'Irene_Lenoir', 'Diomedes_Sebastianus', 'Ding_Li_Ying', 'Dag_Alreksson', 'David_Urry', 'Jana_von_Drachenklaue', 'Karl_of_Meerstapa', 'Sigurðr_Vigurhöfn', 'Simon_von_Beckum', 'Theodora_Bryennissa', 'Michel_Almond_de_Champagne', 'Lucius_Aurelius_Varus', 'Kenric_Burn_of_Northampton', 'Lucan_von_Drachenklaue', 'Culann_mac_Cianain', 'Connar_Tentburner', 'Chivalry', 'Clan_O\'Niall', 'House_Silver_Oak', 'Silver_Dragon', 'Feral_von_Halstern', 'Jana_von_Drachenklaue', 'Northern_Army', 'Allagion_Sebastianus', 'The_Blackwater_Company', 'Avelina_Keyes', 'Brennan_mac_Fearghus', 'Arthur_Watson', 'Angus_O\'Niall', 'Áine_O\'Raghallaigh', 'Alaric_von_Drachenklaue', 'Lucan_von_Drachenklaue'))
Function: Parser::replaceLinkHolders
Error: 2002 Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (localhost)
' in /usr/share/mediawiki1.7/includes/db/Database.php:606
Stack trace:
#0 /usr/share/mediawiki1.7/includes/db/Database.php(561): Database->reportQueryError('Can't connect t...', 2002, 'SELECT page_id,...', 'Parser::replace...', false)
#1 /usr/share/mediawiki1.7/includes/parser/Parser.php(4102): Database->query('SELECT page_id,...', 'Parser::replace...')
#2 /usr/share/mediawiki1.7/includes/parser/Parser.php(334): Parser->replaceLinkHolders('<div>?<table wi...')
#3 /usr/share/mediawiki1.7/includes/OutputPage.php(405): Parser->parse('{{Households|ph...', Object(Title), Object(ParserOptions), true, true, 15778)
#4 /usr/share/mediawiki1.7/includes/OutputPage.php(391): OutputPage->addWikiTextTitle('{{Households|ph...', Object(Title), true, true)
#5 /usr/share/mediawiki1.7/includes/OutputPage.php(500): OutputPage->addWikiTextTitleTidy('{{Households|ph...', Object(Title), true)
#6 /usr/share/mediawiki1.7/includes/DifferenceEngine.php(313): OutputPage->addWikiTextTidy('{{Households|ph...')
#7 /usr/share/mediawiki1.7/includes/DifferenceEngine.php(271): DifferenceEngine->renderNewRevision()
#8 /usr/share/mediawiki1.7/includes/Article.php(729): DifferenceEngine->showDiffPage(false)
#9 /usr/share/mediawiki1.7/includes/Wiki.php(437): Article->view()
#10 /usr/share/mediawiki1.7/includes/Wiki.php(59): MediaWiki->performAction(Object(OutputPage), Object(Article), Object(Title), Object(User), Object(WebRequest))
#11 /var/lib/mediawiki1.7/index.php(93): MediaWiki->initialize(Object(Title), Object(Article), Object(OutputPage), Object(User), Object(WebRequest))
#12 {main}

Exception caught inside exception handler: exception 'DBUnexpectedError' with message 'Error in fetchObject(): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (localhost)' in /usr/share/mediawiki1.7/includes/db/Database.php:735
Stack trace:
#0 /usr/share/mediawiki1.7/includes/db/Database.php(2620): Database->fetchObject(false)
#1 /usr/share/mediawiki1.7/includes/LinkBatch.php(98): ResultWrapper->fetchObject()
#2 /usr/share/mediawiki1.7/includes/LinkBatch.php(78): LinkBatch->addResultToCache(Object(LinkCache), Object(ResultWrapper))
#3 /usr/share/mediawiki1.7/includes/LinkBatch.php(68): LinkBatch->executeInto(Object(LinkCache))
#4 /usr/share/mediawiki1.7/includes/Skin.php(208): LinkBatch->execute()
#5 /usr/share/mediawiki1.7/includes/Skin.php(184): Skin->preloadExistence()
#6 /usr/share/mediawiki1.7/includes/SkinTemplate.php(106): Skin->initPage(Object(OutputPage))
#7 /usr/share/mediawiki1.7/skins/MonoBook.php(24): SkinTemplate->initPage(Object(OutputPage))
#8 /usr/share/mediawiki1.7/includes/SkinTemplate.php(151): SkinMonoBook->initPage(Object(OutputPage))
#9 /usr/share/mediawiki1.7/includes/OutputPage.php(821): SkinTemplate->outputPage(Object(OutputPage))
#10 /usr/share/mediawiki1.7/includes/Exception.php(150): OutputPage->output()
#11 /usr/share/mediawiki1.7/includes/Exception.php(174): MWException->reportHTML()
#12 /usr/share/mediawiki1.7/includes/Exception.php(260): MWException->report()
#13 /usr/share/mediawiki1.7/includes/Exception.php(294): wfReportException(Object(DBQueryError))
#14 [internal function]: wfExceptionHandler(Object(DBQueryError))
#15 {main}