Translation-service for non german unterstandig people:
Es ist ein Datenbankabfragefehler aufgetreten. Dies könnte auf einen Fehler in der Software hindeuten. => A database error occured. This may indicate a bug in the software.
Funktion => Function
Fehler => Error

@Boshomi Thanks for reporting, it seems that the edit was completed ok. Can you reproduce the error again, for that article or another?

Databases were in a poorer state for some hours after the datacenter failover. The actual infrastructure stability was not affected, but there could be some more errors than usual. On my logs, however, those errors were rare (50 for all users in 24 hours) amd those should not happen again in an eventual next failover. They also should not longer be happenning.

Could you confirm that this is true?

@jcrespo no, I can not reproduce this bug.

What I did before: https://de.wikipedia.org/w/index.php?title=Spezial:Beitr%C3%A4ge/Boshomi&offset=20160420181000&target=Boshomi

I opened 60+ articles and mad a simple replace. then I saved the open tabs with Alt+S while changing the tabs with mouse. So I can save up to 3 articles per second.

one of this sessions ended at UTC 18:06:19; between 18:06:19 and 18:07 I mad the same simple edit in the last 27 artikles and started with saving some secondes before 18:08 the diff 153655394 was the first article in this session. The edit with the error message was as 18:07:55 the next edit followed at 18:00:00, I think, I saved the tabs much faster. I suspect a delay in messaging or database near by 18:00

on April 20 I startet edting with this edit https://de.wikipedia.org/w/index.php?title=Benutzer:Boshomi/Test1&diff=prev&oldid=153649934 at UTC 15:00
between 15:00 and 18:10 I mad about 900 edits, the change of the datacenter was no problem, the reported error message was unique.

@jcrespo: I save 3 article per second, but the mean time for simplest edit is about 2 seconds. (yes that is faster than a bot, but I have no timer, I do this per hand)

try to open 60+ pages with chrome/chromium on linux, you can scroll with the mousewheel over the tabs => the browser switch from one tab to another.

hold Alt+E while scroll the mousewheel => all the tabs are in edit mode

faster that Alt+E is to open links like https://de.wikipedia.org/w/index.php?title=Benutzer:Boshomi/Test1&diff=153805019&oldid=153707864 with Linkclump (Browser-Addon)

I make a simple edit, check the diff. When ready I save all the open tabs with Alt+S, normally with one keystroke per page. (holding Alt+S and scroll over the tab is potential faster, but I get a lot of edit conflicts by my self, and it is possible to run into the database limits which is beyond 10 edits per second. )

yes that is not a common traffic pattern. I simple reduced unproductive time to a minimum.