Change 298510 had a related patch set uploaded (by Chad):
Disable content translation

https://gerrit.wikimedia.org/r/298510

It had consumed all connections (the 10000 of them) doing:

UPDATE /* ContentTranslation\Translation::update <user> */  `cx_translations` SET translation_target_title = 'Doaba', translation_source_revision_id = '729218022', translation_source_url = '//en.wikipedia.org/wiki/Doaba', translation_status = 'draft', translation_last_updated_timestamp = '20160712153934', translation_progress = '{\"any\":0.4634964890541099, \"human\":0.3580132176786452, \"mt\":0.10548327137546469, \"mtSectionsCount\":16}', translation_last_update_by = '42573130' WHERE translation_id = '177521' /* da58dc0b53791be4d3bda4ef4224b952 db1031 wikishared 22s */

Change 298510 merged by Chad:
Disable content translation

https://gerrit.wikimedia.org/r/298510

Change 298522 had a related patch set uploaded (by Nikerabbit):
Add ping limiter to cxsave

https://gerrit.wikimedia.org/r/298522

Change 298523 had a related patch set uploaded (by Nikerabbit):
Add rate limiting for cxsave

https://gerrit.wikimedia.org/r/298523

API module request counts shows spikes of over 1000 (per second I assume), assumed to come from one or few users.

Change 298523 merged by jenkins-bot:
Add rate limiting for cxsave

https://gerrit.wikimedia.org/r/298523

Change 298522 merged by jenkins-bot:
Add ping limiter to cxsave

https://gerrit.wikimedia.org/r/298522

Change 298529 had a related patch set uploaded (by Chad):
Add ping limiter to cxsave

https://gerrit.wikimedia.org/r/298529

Change 298529 merged by jenkins-bot:
Add ping limiter to cxsave

https://gerrit.wikimedia.org/r/298529