Hello all,

This is an important announcement for all the tool builders and maintainers who access Wikidata’s data by *querying Labs database replicas directly*.

In April 2019, the Wikidata development team started a heavy redesign of an important table of the database, wb_terms. Over the years, this table has become too big, causing various issues. That’s why we decided to split it into several smaller tables. For more context, you can have a look at previous announcements: April 2019 https://lists.wikimedia.org/pipermail/wikidata/2019-April/012987.html, May 2019 https://lists.wikimedia.org/pipermail/wikidata/2019-May/013052.html.

We encountered a lot of unexpected issues on the road which required us to postpone the timeline, but the final steps of the migration are now happening. We published a blog post https://phabricator.wikimedia.org/phame/post/view/195/coming_to_terms_with_change/ to explain in more detail what we did and why it was important to optimize the database structure.

Here’s an overview of what happened, what are the next steps and how you can update your code:

- The new structure is now in place on Labs. You can read more details on this documentation page https://doc.wikimedia.org/mediawiki-extensions-Wikibase/master/php/md_docs_storage_terms.html - Wikidata is entirely reading from and writing to the new tables since March 18th, which means the existing wb_terms table is *not updated anymore* - This means that any tools that are still reading from wb_terms and updating Wikidata based on its content have to be updated as soon as possible - In order to fully deprecate the table and make it clear that it is outdated, the wb_terms will be renamed to wb_terms_no_longer_updated on Monday, *March 30th*. Tools still querying this table at that date will certainly encounter errors. - To get an overview on how to update your queries, you can have a look at these examples https://phabricator.wikimedia.org/T221767

If you have questions or encounter any issues, please write on this Phabricator ticket https://phabricator.wikimedia.org/T208425 or write me an email.

We apologize for the delay and the lack of recent updates regarding this change.

Cheers,