I tried to change one textual line in [https://www.wikidata.org/wiki/User:KaMan/brudnopis] but got fatal exception instead of saved page:
MediaWiki internal error.
Original exception: [W@@wBgpAICoAABxe0NAAAABH] 2018-11-17 06:08:11: Fatal exception of type "Wikimedia\Rdbms\DBExpectedError"
Exception caught inside exception handler.
Set $wgShowExceptionDetails = true; at the bottom of LocalSettings.php to show detailed debugging information.
From logstash
[W@@wBgpAICoAABxe0NAAAABH] /w/index.php?title=User:KaMan/brudnopis&action=submit Wikimedia\Rdbms\DBExpectedError from line 196 of /srv/mediawiki/php-1.33.0-wmf.4/includes/libs/rdbms/database/DatabaseMysqli.php: Could not select database 'metawiki'.
0 /srv/mediawiki/php-1.33.0-wmf.4/includes/libs/rdbms/database/Database.php(2312): Wikimedia\Rdbms\DatabaseMysqli->doSelectDomain(Wikimedia\Rdbms\DatabaseDomain)
#1 /srv/mediawiki/php-1.33.0-wmf.4/includes/libs/rdbms/loadbalancer/LoadBalancer.php(1015): Wikimedia\Rdbms\Database->selectDomain(Wikimedia\Rdbms\DatabaseDomain)
#2 /srv/mediawiki/php-1.33.0-wmf.4/includes/libs/rdbms/loadbalancer/LoadBalancer.php(871): Wikimedia\Rdbms\LoadBalancer->openForeignConnection(integer, string, integer)
#3 /srv/mediawiki/php-1.33.0-wmf.4/includes/libs/rdbms/loadbalancer/LoadBalancer.php(750): Wikimedia\Rdbms\LoadBalancer->openConnection(integer, string, integer)
#4 /srv/mediawiki/php-1.33.0-wmf.4/includes/libs/rdbms/loadbalancer/LoadBalancer.php(835): Wikimedia\Rdbms\LoadBalancer->getConnection(integer, array, string, integer)
#5 /srv/mediawiki/php-1.33.0-wmf.4/extensions/GlobalUserPage/includes/GlobalUserPage.php(202): Wikimedia\Rdbms\LoadBalancer->getConnectionRef(integer, array, string)
#6 /srv/mediawiki/php-1.33.0-wmf.4/extensions/GlobalUserPage/includes/GlobalUserPage.php(177): MediaWiki\GlobalUserPage\GlobalUserPage::getCentralTouched(User)
#7 /srv/mediawiki/php-1.33.0-wmf.4/extensions/GlobalUserPage/includes/Hooks.php(57): MediaWiki\GlobalUserPage\GlobalUserPage::shouldDisplayGlobalPage(Title)
#8 /srv/mediawiki/php-1.33.0-wmf.4/includes/Hooks.php(174): MediaWiki\GlobalUserPage\Hooks::onTitleIsAlwaysKnown(Title, NULL)
#9 /srv/mediawiki/php-1.33.0-wmf.4/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL)
#10 /srv/mediawiki/php-1.33.0-wmf.4/includes/Title.php(4751): Hooks::run(string, array)
#11 /srv/mediawiki/php-1.33.0-wmf.4/includes/parser/Parser.php(2470): Title->isAlwaysKnown()
#12 /srv/mediawiki/php-1.33.0-wmf.4/includes/parser/Parser.php(2169): Parser->replaceInternalLinks2(string)
#13 /srv/mediawiki/php-1.33.0-wmf.4/includes/parser/Parser.php(1379): Parser->replaceInternalLinks(string)
#14 /srv/mediawiki/php-1.33.0-wmf.4/includes/parser/Parser.php(482): Parser->internalParse(string)
#15 /srv/mediawiki/php-1.33.0-wmf.4/includes/StubObject.php(112): Parser->parse(string, Title, ParserOptions, boolean, boolean, NULL)
#16 /srv/mediawiki/php-1.33.0-wmf.4/includes/StubObject.php(138): StubObject->_call(string, array)
#17 /srv/mediawiki/php-1.33.0-wmf.4/includes/content/WikitextContent.php(341): StubObject->__call(string, array)
#18 /srv/mediawiki/php-1.33.0-wmf.4/includes/content/AbstractContent.php(517): WikitextContent->fillParserOutput(Title, NULL, ParserOptions, boolean, ParserOutput)
#19 /srv/mediawiki/php-1.33.0-wmf.4/includes/Revision/RenderedRevision.php(243): AbstractContent->getParserOutput(Title, NULL, ParserOptions, boolean)
#20 /srv/mediawiki/php-1.33.0-wmf.4/includes/Revision/RenderedRevision.php(211): MediaWiki\Revision\RenderedRevision->getSlotParserOutputUncached(WikitextContent, boolean)
#21 /srv/mediawiki/php-1.33.0-wmf.4/includes/Revision/RevisionRenderer.php(175): MediaWiki\Revision\RenderedRevision->getSlotParserOutput(string)
#22 /srv/mediawiki/php-1.33.0-wmf.4/includes/Revision/RevisionRenderer.php(128): MediaWiki\Revision\RevisionRenderer->combineSlotOutput(MediaWiki\Revision\RenderedRevision, array)
#23 [internal function]: Closure$MediaWiki\Revision\RevisionRenderer::getRenderedRevision#2(MediaWiki\Revision\RenderedRevision, array)
#24 /srv/mediawiki/php-1.33.0-wmf.4/includes/Revision/RenderedRevision.php(175): call_user_func(Closure$MediaWiki\Revision\RevisionRenderer::getRenderedRevision#2;1031, MediaWiki\Revision\RenderedRevision, array)
#25 /srv/mediawiki/php-1.33.0-wmf.4/includes/Storage/DerivedPageDataUpdater.php(1260): MediaWiki\Revision\RenderedRevision->getRevisionParserOutput()
#26 /srv/mediawiki/php-1.33.0-wmf.4/includes/Storage/DerivedPageDataUpdater.php(1230): MediaWiki\Storage\DerivedPageDataUpdater->getCanonicalParserOutput()
#27 /srv/mediawiki/php-1.33.0-wmf.4/includes/page/WikiPage.php(1996): MediaWiki\Storage\DerivedPageDataUpdater->getPreparedEdit()
#28 /srv/mediawiki/php-1.33.0-wmf.4/extensions/SpamBlacklist/includes/SpamBlacklistHooks.php(31): WikiPage->prepareContentForEdit(WikitextContent)
#29 /srv/mediawiki/php-1.33.0-wmf.4/includes/Hooks.php(174): SpamBlacklistHooks::filterMergedContent(RequestContext, WikitextContent, Status, string, User, boolean)
#30 /srv/mediawiki/php-1.33.0-wmf.4/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL)
#31 /srv/mediawiki/php-1.33.0-wmf.4/includes/EditPage.php(1751): Hooks::run(string, array)
#32 /srv/mediawiki/php-1.33.0-wmf.4/includes/EditPage.php(2195): EditPage->runPostMergeFilters(WikitextContent, Status, User)
#33 /srv/mediawiki/php-1.33.0-wmf.4/includes/EditPage.php(1578): EditPage->internalAttemptSave(NULL, boolean)
#34 /srv/mediawiki/php-1.33.0-wmf.4/includes/EditPage.php(677): EditPage->attemptSave(NULL)
#35 /srv/mediawiki/php-1.33.0-wmf.4/includes/actions/EditAction.php(60): EditPage->edit()
#36 /srv/mediawiki/php-1.33.0-wmf.4/includes/actions/SubmitAction.php(38): EditAction->show()
#37 /srv/mediawiki/php-1.33.0-wmf.4/includes/MediaWiki.php(501): SubmitAction->show()
#38 /srv/mediawiki/php-1.33.0-wmf.4/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title)
#39 /srv/mediawiki/php-1.33.0-wmf.4/includes/MediaWiki.php(862): MediaWiki->performRequest()
#40 /srv/mediawiki/php-1.33.0-wmf.4/includes/MediaWiki.php(517): MediaWiki->main()
#41 /srv/mediawiki/php-1.33.0-wmf.4/index.php(42): MediaWiki->run()
#42 /srv/mediawiki/w/index.php(3): include(string)
#43 {main}