Fixing T314703 introduced a regression in the way the lag is reported to both users (from the UI) and in the prometheus metric blazegraph_lastupdated.
The reason is that it is handled by a triple in the database as <http://www.wikidata.org> schema:dateModified ?date but enabling proper URI schemes did cause this triple to be updated as <https://commons.wikimedia.org> schema:dateModified ?date.
Given that this is both hardcoded in the UI and puppet I'm tempted to also hardcode this triple at the updater level (T278246 describes a better way to report lag so it might be better to invest efforts in it rather than on this ticket).
AC:
- https://grafana-rw.wikimedia.org/d/000000489/wikidata-query-service?orgId=1&var-cluster_name=wcqs reports the same lag as latency in https://grafana-rw.wikimedia.org/d/fdU5Zx-Mk/wdqs-streaming-updater?orgId=1&var-site=eqiad&var-k8sds=eqiad%20prometheus%2Fk8s&var-opsds=eqiad%20prometheus%2Fops&var-cluster_name=wcqs
- https://commons-query.wikimedia.org reports proper lag information