0 data cache usage since May 13

team id: team_f2ZrGqeerKmwRS4VUrIVxZXy
project id: prj_8tB87CjV1UUqEqW9PYmV7wS5Mp7M

My team appears to have 0 data cache usage from May 13 onwards despite definitely using unstable_cache and "use cache". I had a production deploy on May 7th and on May 17th, so no code changes on the 13th. The May 17th deploy included a switch to using "use cache" via Next 15.3.2, and I can see “Data Cache” entries in the External APIs section of requests, so I’m fairly sure caching is working, I’m just not seeing its usage reflected.

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Hello,

We are investigating this.

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Could you please provide request ids where they are using unstable_cache - I can’t find any and I don’t see anything in usage facts indicating that they are hitting cache.

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I can’t provide request IDs for any deployment older than May 17th due to a drastic database schema update, but for the current deployment:

8lln5-1747623847644-f4475f9fad74: hard navigation so it’s loading some layout data. Under External APIs there’s an entry called “Data Cache” that gives the URL sfo1.suspense-cache.vercel-infra.com/ when clicking/copying.

What confuses me is that this route has 4 usages of "use cache". If these weren’t being cached, there would be 8 extra external requests listed.

8mm9t-1747624272626-0cbbc8c94c63: this is a soft navigation and lists a “Data Cache” entry. If that entry wasn’t being cached, there would be 3 more external requests.

Is this a case of all data cache usage being collapsed into a single “external APIs” entry?

If you’re able to see the domain and everything, then a hard navigation to / will trigger two usages of "use cache". One revalidates every 75s, one every 4 hours.

edit: noticing now that my data cache bandwidth has stopped being reported as of May 17th and my revalidations have plummeted, when all I’ve done is replace unstable_cache usage with "use cache".

We checked and neither of those requests are unstable_cache - they are both tag checks which happen with “use cache” and won’t trigger data cache usage.

Sorry, I’m not following. “use cache” is the intended replacement for unstable_cache which uses the suspense/data cache for storage like unstable_cache does/did, right?

request id 9xfhn-1747677469928-389e995d5ac8 is a route that when soft navigated to, only ever loads data from a function using “use cache”, and the tag gets revalidated with a cron job every hour. In that request, the only external API entries are “Data Cache” and Sentry, no database call. So what’s actually going on here? What is this “Data Cache” entry if “use cache” doesn’t use the data cache?

I can understand if the answer is as simple as ““use cache” doesn’t use the data cache by design, therefore it won’t be reflected in Vercel data cache usage stats”, but this doesn’t explain the lack of data cache usage between May 13th and May 17. There was no code changes made between May 7 and May 17, so I would expect to see data cache usage from the 13th to the 17th at the very minimum.

For now, only use cache: remote will use data cache. use cache does use some of the suspense cache APIs though for tags management, until the new version runtime changes we are going to roll out.

Although the issue with data cache usage not reporting has been resolved

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Alright I switched over to using "use cache: remote" and nothing seems to have changed in the usage reporting or request logs. Things do appear to still be caching like before so I’ll just leave it as-is for now then. Thanks.

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