Sticking this here for reference at least. Table shouldn't be used by Translate code (from having looked at it), but from somewhere it is...

2013-03-07 23:42:52 mw1198 mediawikiwiki: [2b17d602] /w/api.php Exception from line 255 of /usr/local/apache/common-local/php-1.21wmf11/includes/db/DatabaseMysql.php: Error in numRows(): Table 'mediawikiwiki.revtag_type' doesn't exist (10.64.0.14)
#0 /usr/local/apache/common-local/php-1.21wmf11/includes/db/DatabaseUtility.php(124): DatabaseMysql->numRows(Object(ResultWrapper))
#1 /usr/local/apache/common-local/php-1.21wmf11/includes/db/DatabaseUtility.php(176): ResultWrapper->numRows()
#2 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/utils/TranslateMetadata.php(28): ResultWrapper->rewind()
#3 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/MessageGroups.php(641): TranslateMetadata::get('agg-Help:Naraya...', 'name')
#4 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/MessageGroups.php(144): MessageGroups::getAggregateGroups()
#5 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/MessageGroups.php(41): MessageGroups::loadGroupDefinitions()
#6 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/MessageGroups.php(406): MessageGroups::init()
#7 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/utils/MessageIndex.php(97): MessageGroups->getGroups()
#8 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/utils/MessageIndexRebuildJob.php(31): MessageIndex->rebuild()
#9 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/utils/MessageIndexRebuildJob.php(46): MessageIndexRebuildJob->run()
#10 /usr/local/apache/common-local/php-1.21wmf11/extensions/Translate/api/ApiAggregateGroups.php(135): MessageIndexRebuildJob->insert()
#11 /usr/local/apache/common-local/php-1.21wmf11/includes/api/ApiMain.php(839): ApiAggregateGroups->execute()
#12 /usr/local/apache/common-local/php-1.21wmf11/includes/api/ApiMain.php(379): ApiMain->executeAction()
#13 /usr/local/apache/common-local/php-1.21wmf11/includes/api/ApiMain.php(350): ApiMain->executeActionWithErrorHandling()
#14 /usr/local/apache/common-local/php-1.21wmf11/api.php(77): ApiMain->execute()

Version: master
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=53792