This is a bad time for Wikidata Query Service. We had a few issues
last week to update WDQS and reload all data. During this data reload,
we are running on a single server. And now this server is starting to
behave erratically.
I honestly do not know yet what is happening except that we see a lot
of file (pipes actually) left open and that WDQS stops responding.
Investigation is going on [1] and we'll let you know what we find.
Sorry for the inconvenience and thank you all for your patience!
[1]
https://phabricator.wikimedia.org/T134238
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Guillaume Lederrey
Operations Engineer, Discovery
Wikimedia Foundation