how to tell if data from cache globally? I want to collect the cache rate metrics.

[lili21]

Here is my use case. I'm trying to collect some metrics , and measure the performance improvement from RQ.

Beside, I'm using the persister with RQ. and It would be helpful If I can collect the cache rate metrics and adjust the cache strategy.

[lili21]

I've tried get the info from queryCache.subsribe method

const queryCache = new QueryCache();

queryCache.subscribe(event => {
  if (event.query.isStale()) {
  } else {
  }
})

but the callback function will be called multiple time for every query.

[TkDodo]

I want to collect the cache rate metrics.

Every re-render will read data from the cache, and thus be a “cache hit”. That’s because data lives exclusively in the cache. I’m not really sure how you would quantify a “cache hit”? Maybe something like: “If a new component mounts and that component needs some data, but its already in the cache and not stale” ? But you have to be more specific. “Cache rate metrics” sounds like it’s a something you have to present to meet some managerial requirements but on its own, it doesn’t make much sense in this context...

Note: if what I said is what you want, filter your events down to the type ’observerAdded’.

[lili21]

Got it. I'm more care about the page visit performance, like LCP. the LCP should be fast if the data is from cache. it would be nice if I can tell it from re-render.