hash•2mo ago

Invalidating useQuery cache on refetch

Hey, I'm working on a language learning app, it pulls 10 questions from my convex DB for each quiz game. However I noticed the questions are cached, so restarting the game just reshuffles the 10 or so questions it pulls at the start, and creating a new game doesn't actually pull a new set of questions which is how it's configured to behave. Anyone know how to invalidate cached queries? I couldn't find my answer in the docs

9 Replies

Convex Bot•2mo ago

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Clever Tagline•2mo ago

I'm not familiar with invalidating cached queries. However, it might be good to see your current process. Could you share a code snippet or two from the relevant parts of the app?

hashOP•2mo ago

sure

Clever Tagline•2mo ago

Searching the docs for "cache invalidation," one of the results that came back was this Stack article. Maybe it'll help? https://stack.convex.dev/caching-in

The Ultimate Caching Definition: Invalidation, Optimization, and La...

A cache is a non-authoritative representation of data maintained for performance reasons. Find out what these words mean and when you should care abou...

Clever Tagline•2mo ago

I suggest trying the search in the docs. It includes results from Stack articles and this Discord server.

hashOP•2mo ago

Ah, I didn't see that I was trying to find something in the docs for querying, thanks That's more of an article about cache in general (contextually talking abut redis) I'm looking for invalidation of cache'd queries. I'm not super familiar with the architecture of convex so not sure where to start really, lots of stuff is abstracted away. Below is the useQuery hook which is being used inside a useGameLogic hook for handling all the logic for each quiz game. Each quiz game is just 10 multiple choice questions.

const questions = useQuery(api.questions.getQuestions, {
    questionType,
    // numberOfQuestions: filters.numberOfQuestions,
  });

const questions = useQuery(api.questions.getQuestions, {
    questionType,
    // numberOfQuestions: filters.numberOfQuestions,
  });

The issue is that each time a user starts a quiz, it's just reshuffling the already fetched questions and not pulling a completely fresh set from the DB. That's what I mean by cache. Hope this helps. Let me know if you want to see anything else.

Sara•2mo ago

if you haven't already noticed, the useQuery works as a use memo, if the args hasn't changed, there's no way of sending a new value, one of the tricks I do in this case but please know this is not an official source, I just do some wild things is to have a "useState" with a random key, and pass it with the args like: changingValueOnRequest && myActualArgs ? {myActualArgs}:"skip" this would invoke it every time you click it and maybe pass this key down so it actually invokes this change

Clever Tagline•2mo ago

That reminds me of something that I think I heard/read: pass the current time to the query. Even though the value is not used, the fact that the current time is always changing will invalidate the cache...I think. Again, this is a slightly fuzzy recollection that I recall reading once or twice, and I've never had a need to put it into practice myself so I can't verify how well it works, but maybe...?

hashOP•2mo ago

Yeah apparently you can configure it to take in date-time as an arg or configure a function to give you a deterministic seed based on date-time and pass that as an arg Just waiting for my lead to see my msgs :Waiting:

Invalidating useQuery cache on refetch

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