*(If your third-party tool does not read data from [wbc_entity_usage] via Wiki Replicas or SQL, please ignore this email)*

Hello everyone, planning is underway to move the Wikibase [wbc_entity_usage] tables for all wikis to a different database cluster: “x1 extension cluster”, to improve database space usage and potentially free up hundreds of GBs per sN cluster [0].

We expect that few, if any, third-party tools rely directly on this table — but before making any breaking changes, we want to confirm that. If your tool uses this table, hearing from you will help us understand how many tools are affected and what that usage looks like, so we can plan the migration accordingly.

[wbc_entity_usage] tracks which Wikidata entities are used on a given Wiki’s pages, and also powers Wikidata-triggered Recent Changes and Watchlist injections to client Wikis.

If you operate a tool that reads from [wbc_entity_usage] table

- via Wiki Replicas / direct SQL - including JOINs queries to other MediaWiki tables

Then please reply to this email or comment on [1] — even a simple “yes, I am” is helpful! If you’re able to share more, it helps us even further:

-

The Tool name and location (e.g. Toolforge, repo link) -

If your query JOIN’s [wbc_entity_usage] with other tables, please tell us which (e.g. "page", "revision") -

How often the queries run [wbc_entity_usage], (e.g. real-time, daily, weekly, manually).

*Please be aware:* Cross-cluster JOIN queries will no longer work *after* the migration is completed, so they will need to be adjusted.

However, old and new tables will be kept ‘in sync’ during the transition period so operating queries should continue to function until the cutoff data / the old tables are turned off. [2]

If you have questions, feel free to reply. If you want to report an issue, please comment on [1].

[0] - https://phabricator.wikimedia.org/T424133 [1] - https://phabricator.wikimedia.org/T430289 [2] - https://phabricator.wikimedia.org/T430289 https://phabricator.wikimedia.org/T424440

https://phabricator.wikimedia.org/T430289Thank you, Danny