When trying to upgrade a mediawiki from 1.27 to 1.33.1 i got the following error message:
MWException from line 463 of /var/www/mediawiki/code/includes/installer/MysqlUpdater.php: Missing rc_timestamp field of recentchanges table. Should not happen.
This is totally misleading. In my case the whole database was missing and I'd expect the updater to say so.