As witnessed today, when the Commons database goes down, this leads to db errors after edits on many pages on unrelated databases.

This is possibly caused by GlobalUsage::onLinksUpdateComplete hook. This retrieves the GlobalUsage db on every linksupdate, even if there are no images at all on the page in question apparently.

I'm suggestion we check the size of missingFiles.

There are wider consequences however. Possibly we would want to create a system where jobs like this are postponed if the global database is not available ? (a refreshLinks job ?)

Version: unspecified
Severity: trivial