Hello all!
We are having some issues with 2 of the Wikidata Query Service servers. So far, the issue looks like data corruption, probably related to an issue in Blazegraph itself (the database engine behind Wikidata Query Service). The issue prevents updates to the data, but reads are unaffected as far as we can tell.
The 2 affected servers are part of the internal WDQS cluster, so the public wdqs endpoint [1] is not affected. Data is lagging on the internal eqiad endpoint, so Mediawiki functionalities that use WDQS are at the moment not seeing the latest updates to Wikidata.
We are reaching out to the Blazegraph team via Github [2] and via private contacts that we have. We hope to identify the root cause of the issue so that we can fix it for good, but this looks like a hard problem. Failing that, we will reimport the full data set.
You can follow the upstream issue on Github [2] and on Phabricator on our side [3].
Sorry for the inconvenience and thank you for your patience!
Have fun,
Guillaume
[1] https://query.wikidata.org/ [2] https://github.com/blazegraph/database/issues/114 [3] https://phabricator.wikimedia.org/T213134