We are currently investigating how we can support this in T383446 and can report back here once we confirm this will be feasible.

Tagging for schema-change as there's a single column addition on globaljsonlinks which in production lives in x1.commonswiki. We can deploy code safely before the schema change in a pinch by disabling the $wgTraclGlobalJsonLinksNamespaces feature flag, in which case it will use canonical namespaces or numeric fallbacks for cases of custom namespaces not present on Commons.

Change #1111690 had a related patch set uploaded (by Bvibber; author: Bvibber):

[mediawiki/extensions/JsonConfig@master] Support for Data: page global usage display

https://gerrit.wikimedia.org/r/1111690

Change #1111690 merged by jenkins-bot:

[mediawiki/extensions/JsonConfig@master] Support for Data: page global usage display

https://gerrit.wikimedia.org/r/1111690

I was happy that this finally works, but I’m not that happy with the performance. I opened https://commons.wikimedia.org/wiki/Data:I18n/Documentation.tab, which I was sure that will have some links, to see how it looks like – and I saw more than 100k links! Usually, query pages show 50 links by default, with up to 500 being available via links/preferences and 5000 being the hard limit that can be reached by tweaking the URL. This page returns over 20 times more than the usual hard limit! I don’t think this is okay from either a frontend performance or a backend/DB performance viewpoint. Please make it so that similarly to GlobalUsage, only a handful of links appear directly on the page, with everything else being available from a – paginated – special page.

In T371300#10644771, @Tacsipacsi wrote:

I was happy that this finally works, but I’m not that happy with the performance. I opened https://commons.wikimedia.org/wiki/Data:I18n/Documentation.tab, which I was sure that will have some links, to see how it looks like – and I saw more than 100k links! Usually, query pages show 50 links by default, with up to 500 being available via links/preferences and 5000 being the hard limit that can be reached by tweaking the URL. This page returns over 20 times more than the usual hard limit! I don’t think this is okay from either a frontend performance or a backend/DB performance viewpoint. Please make it so that similarly to GlobalUsage, only a handful of links appear directly on the page, with everything else being available from a – paginated – special page.

Yep, that was due to a little corner-cutting porting logic over from GlobalUsage; we hadn't quite realized so many common usages would come up so quickly and skipped the pager. :) Pager code has now been ported over and seems to be working on T371300; once we pass code review we'll deploy, probably early next week.

On very widely used data pages it will still need to hit a lot of rows in the database due to the way the indexes don't quite match what we want to display, but won't have to format them all and return them all as HTML so should be much more efficient.