Hello all!

We are happy to announce the availability of Wikimedia Commons Query Service (WCQS): https://wcqs-beta.wmflabs.org/.

This is a beta SPARQL endpoint exposing the Structured Data on Commons (SDoC) dataset. This endpoint can federate with WDQS. More work is needed as we iterate on the service, but feel free to begin using the endpoint. Known limitations are listed below:

* The service is a beta endpoint that is updated via weekly dumps. Some caveats include limited performance, expected downtimes, and no interface, naming, or backward compatibility stability guarantees.
    * The service is hosted on Wikimedia Cloud Services, with limited resources and limited monitoring. This means there may be random unplanned downtime.
The data will be reloaded weekly from dumps. The service will be down during data reload. With the current amount of SDoC data, downtime will last approximately 4 hours, but this may increase as SDoC data grows.
    * Due to an issue with the dump format, the data currently only dates back to July 5th. We’re working on getting more up-to-date data and hope to have a solution soon. (https://phabricator.wikimedia.org/T258507 and https://phabricator.wikimedia.org/T258474)
    * The MediaInfo concept URIs (e.g. http://commons.wikimedia.org/entity/M37200540) are currently HTTP; we may change these to HTTPS in the near future. Please comment on T258590 if you have concerns about this change.
* The service is restricted behind OAuth authentication, backed by Commons. You will need an account on Commons to access the service. This is so that we can contact abusive bots and/or users and block them selectively as a last resort if needed.
    * Please note that to correctly logout of the service, you need to use the logout link in WCQS - logging out of just Wikimedia Commons will not work for WCQS. This limitation will be lifted once we move to production.
* No documentation on the service is available yet. In particular, no examples are provided yet. You can add your own examples at https://commons.wikimedia.org/wiki/Commons:SPARQL_query_service/queries/examples following the format at https://www.wikidata.org/wiki/Wikidata:SPARQL_query_service/queries/examples.
    * Please use the SPARQL template. Note that while there is currently a bug that doesn’t allow us to change the “Try it!” link endpoint, the examples will be displayed correctly on the WCQS GUI.

* WCQS is a work in progress and some bugs are to be expected, especially related to generalizing WDQS to fit SDoC data. For example, current bugs include:
    * URI prefixes specific for SDoC data don’t yet work - you need to use full URIs if you want to query using them. Relations and Q items are defined by Wikidata’s URI prefixes, so they work correctly.
    * Autocomplete for SDoC items doesn’t work - without prefixes they’d be unusable anyway, but additional work will be required after we inject SDoC URI prefixes into WCQS GUI.
    * If you find any additional bugs or issues, please report them via Phabricator with the tag wikidata-query-service.
* We do plan to move the service to production, but we don’t have a timeline on that yet. We want to emphasize that while we do expect a SPARQL endpoint to be part of a medium to long-term solution, it will only be part of that solution. Even once the service is production-ready, it will still have limitations in terms of timeouts, expensive queries, and federation. Some use cases will need to be migrated, over time, to better solutions - once those solutions exist.

Have fun!


Guillaume Lederrey
Engineering Manager, Search Platform
Wikimedia Foundation