MediaWiki internal error.

Original exception: [3a0c64f1] /wiki/api.php Exception from line 1006 of /var/www/wcup/htdocs/wiki/includes/db/Database.php: DB connection error: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (localhost)
Backtrace:
#0 /var/www/wcup/htdocs/wiki/includes/db/LoadBalancer.php(771): DatabaseBase->reportConnectionError(string)
#1 /var/www/wcup/htdocs/wiki/includes/db/LoadBalancer.php(494): LoadBalancer->reportConnectionError()
#2 /var/www/wcup/htdocs/wiki/includes/GlobalFunctions.php(3632): LoadBalancer->getConnection(integer, array, boolean)
#3 /var/www/wcup/htdocs/wiki/includes/cache/LocalisationCache.php(1153): wfGetDB(integer)
#4 /var/www/wcup/htdocs/wiki/includes/cache/LocalisationCache.php(401): LCStoreDB->get(string, string)
#5 /var/www/wcup/htdocs/wiki/includes/cache/LocalisationCache.php(447): LocalisationCache->isExpired(string)
#6 /var/www/wcup/htdocs/wiki/includes/cache/LocalisationCache.php(323): LocalisationCache->initLanguage(string)
#7 /var/www/wcup/htdocs/wiki/includes/cache/LocalisationCache.php(257): LocalisationCache->loadItem(string, string)
#8 /var/www/wcup/htdocs/wiki/languages/Language.php(472): LocalisationCache->getItem(string, string)
#9 /var/www/wcup/htdocs/wiki/includes/search/SearchEngine.php(353): Language->getNamespaces()
#10 /var/www/wcup/htdocs/wiki/includes/User.php(1429): SearchEngine::searchableNamespaces()
#11 /var/www/wcup/htdocs/wiki/includes/User.php(4760): User::getDefaultOptions()
#12 /var/www/wcup/htdocs/wiki/includes/User.php(2515): User->loadOptions()
#13 /var/www/wcup/htdocs/wiki/includes/context/RequestContext.php(311): User->getOption(string)
#14 /var/www/wcup/htdocs/wiki/includes/StubObject.php(185): RequestContext->getLanguage()
#15 /var/www/wcup/htdocs/wiki/includes/StubObject.php(158): StubUserLang->_newObject()
#16 /var/www/wcup/htdocs/wiki/includes/StubObject.php(104): StubObject->_unstub(string, integer)
#17 /var/www/wcup/htdocs/wiki/includes/StubObject.php(178): StubObject->_call(string, array)
#18 /var/www/wcup/htdocs/wiki/includes/cache/MessageCache.php(809): StubUserLang->__call(string, array)
#19 /var/www/wcup/htdocs/wiki/includes/cache/MessageCache.php(809): StubUserLang->getCode()
#20 /var/www/wcup/htdocs/wiki/includes/cache/MessageCache.php(754): MessageCache->getMessageFromFallbackChain(StubUserLang, string, string, boolean)
#21 /var/www/wcup/htdocs/wiki/includes/Message.php(1039): MessageCache->get(string, boolean, StubUserLang)
#22 /var/www/wcup/htdocs/wiki/includes/Message.php(674): Message->fetchMessage()
#23 /var/www/wcup/htdocs/wiki/includes/Message.php(766): Message->toString()
#24 /var/www/wcup/htdocs/wiki/includes/filerepo/FileRepo.php(1733): Message->text()
#25 /var/www/wcup/htdocs/wiki/includes/filerepo/FileRepo.php(1853): FileRepo->getDisplayName()
#26 /var/www/wcup/htdocs/wiki/includes/filerepo/ForeignAPIRepo.php(471): FileRepo->getInfo()
#27 /var/www/wcup/htdocs/wiki/includes/api/ApiQueryFileRepoInfo.php(83): ForeignAPIRepo->getInfo()
#28 [internal function]: ApiQueryFileRepoInfo->{closure}(ForeignAPIRepo)
#29 /var/www/wcup/htdocs/wiki/includes/filerepo/RepoGroup.php(371): call_user_func_array(Closure, array)
#30 /var/www/wcup/htdocs/wiki/includes/api/ApiQueryFileRepoInfo.php(84): RepoGroup->forEachForeignRepo(Closure)
#31 /var/www/wcup/htdocs/wiki/includes/api/ApiQueryFileRepoInfo.php(67): ApiQueryFileRepoInfo->getProps()
#32 /var/www/wcup/htdocs/wiki/includes/api/ApiBase.php(364): ApiQueryFileRepoInfo->getAllowedParams(integer)
#33 /var/www/wcup/htdocs/wiki/includes/api/ApiBase.php(1935): ApiBase->getFinalParams(integer)
#34 /var/www/wcup/htdocs/wiki/includes/api/ApiBase.php(1861): ApiBase->makeHelpMsgParameters()
#35 /var/www/wcup/htdocs/wiki/includes/api/ApiQuery.php(580): ApiBase->makeHelpMsg()
#36 /var/www/wcup/htdocs/wiki/includes/api/ApiQuery.php(557): ApiQuery->makeHelpMsgHelper(string)
#37 /var/www/wcup/htdocs/wiki/includes/api/ApiMain.php(1299): ApiQuery->makeHelpMsg()
#38 /var/www/wcup/htdocs/wiki/includes/api/ApiMain.php(1275): ApiMain->reallyMakeHelpMsg()
#39 /var/www/wcup/htdocs/wiki/includes/api/ApiMain.php(678): ApiMain->makeHelpMsg()
#40 /var/www/wcup/htdocs/wiki/includes/api/ApiMain.php(408): ApiMain->substituteResultWithError(UsageException)
#41 /var/www/wcup/htdocs/wiki/includes/api/ApiMain.php(366): ApiMain->handleException(UsageException)
#42 /var/www/wcup/htdocs/wiki/includes/api/ApiMain.php(335): ApiMain->executeActionWithErrorHandling()
#43 /var/www/wcup/htdocs/wiki/api.php(85): ApiMain->execute()
#44 {main}

Exception caught inside exception handler: [99ae540d] /wiki/api.php Exception from line 1006 of /var/www/wcup/htdocs/wiki/includes/db/Database.php: DB connection error: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (localhost)
Backtrace:
#0 /var/www/wcup/htdocs/wiki/includes/db/LoadBalancer.php(771): DatabaseBase->reportConnectionError(string)
#1 /var/www/wcup/htdocs/wiki/includes/db/LoadBalancer.php(494): LoadBalancer->reportConnectionError()
#2 /var/www/wcup/htdocs/wiki/includes/GlobalFunctions.php(3632): LoadBalancer->getConnection(integer, array, boolean)
#3 /var/www/wcup/htdocs/wiki/includes/cache/LinkCache.php(251): wfGetDB(integer)
#4 /var/www/wcup/htdocs/wiki/includes/Title.php(3156): LinkCache->addLinkObj(Title)
#5 /var/www/wcup/htdocs/wiki/includes/Title.php(952): Title->getArticleID(integer)
#6 /var/www/wcup/htdocs/wiki/includes/content/ContentHandler.php(260): Title->getContentModel()
#7 /var/www/wcup/htdocs/wiki/includes/Title.php(4735): ContentHandler::getForTitle(Title)
#8 /var/www/wcup/htdocs/wiki/includes/OutputPage.php(1981): Title->getPageLanguage()
#9 /var/www/wcup/htdocs/wiki/includes/OutputPage.php(2065): OutputPage->addAcceptLanguage()
#10 /var/www/wcup/htdocs/wiki/includes/GlobalFunctions.php(2154): OutputPage->sendCacheControl()
#11 /var/www/wcup/htdocs/wiki/includes/exception/MWException.php(230): wfHttpError(integer, string, string)
#12 /var/www/wcup/htdocs/wiki/includes/exception/MWExceptionHandler.php(45): MWException->report()
#13 /var/www/wcup/htdocs/wiki/includes/exception/MWExceptionHandler.php(141): MWExceptionHandler::report(DBConnectionError)
#14 [internal function]: MWExceptionHandler::handle(DBConnectionError)
#15 {main}