revalidatePath Not Working

[gchallen]

Brief Description of the Bug

Calling revalidatePath does not remove cached data from the Redis cache and force a rebuild of an ISR page.

Severity

This seems like it should work.

Frequency of Occurrence

Always.

Steps to Reproduce
Provide detailed steps to reproduce the behavior, including any specific conditions or configurations where the bug occurs:

1. Set up a Redis-only cache
2. Load a page generated using ISR
3. Verify that the page is cached by Redis
4. Call revalidatePath in a route handler, for example in a POST method intended for on-demand revalidation
5. Verify that the Redis cache still contains the key that should be removed
6. Reload the page and view the stale data

Expected vs. Actual Behavior

revalidatePath should remove the cached data and force the page to be rebuilt.

Environment:

• OS: Kubernetes running Linux pods in production
• 18.19.0
• 0.6.6
• 14.1.0

Attempted Solutions or Workarounds

Creating a Redis client and manually deleting the offending keys in the revalidation POST method seems to work.

Impact of the Bug

Again, this seems like something that should work automatically. It's possible that I've misconfigured something, but my cache configuration is fairly simple.

[better-salmon]

Hello @gchallen! Thank you for opening this issue. I am convinced you configured everything well. I'll try to explain.

When you call the revalidatePath or revalidateTag method from the next/cache module, it does not remove any values from the cache store. It doesn't happen either in the original cache or my cache. These functions add tags and prefixed paths to a revalidatedTags list, which also lives in the cache store. When Next.js retrieves the data, it also retrieves revalidatedTags. Then, my cache does some logic with the tags baked in the cache value and tags from the revalidatedTags list and decides if the page or data is staled.

If your page is updated after calling the revalidatePath or revalidateTag, it works as intended. If this is the case, let's move this issue to discussions. I will check if I can implement the logic you are expecting. But I need more time.

[gchallen]

Thanks for the explanation. I did poke around the code a bit and noticed this logic maintaining the revalidatedTags list, but didn't quite understand how it worked.

My use case is more or less what's described here: performing programmatic on-demand revalidation. Initially I was using the res.revalidate method as shown, but I found that that was fairly slow, and seemed to be actually waiting for the page to rebuild. (I could probably just skip the await I guess.) Given that my endpoint is sometimes revalidating a bunch of pages, I moved to the revalidatePath approach which was much faster—but it's more clear now why...

I don't fully understand the NextJS caching logic, but it does seem like there should be some way to force a page rebuild on the next load, without immediately triggering a page rebuild, which can cause an unnecessary load spike when revalidating many pages, particularly if some of them are infrequently accessed. Manually deleting the page from the Redis cache works for my use case, but only because I've disabled the in-memory caches entirely.