Due to an outage on enwiki earlier today caused by Special:AllPages, it has temporarily been disabled on all wikis pending further investigation. To this extent a public tracking task [1] has been created, and updates will be put there to keep people in the loop. Proper incident should appear on Wikitech at a later date, after the problem has been resolved. Sam [1] https://phabricator.wikimedia.org/T160916