How to use FusionCache with prefetching? about fusioncache HOT 3 CLOSED

Hi @hvgNET and thanks for considering FusionCache.

Sorry for the delay in answering but covid finally got me.

In general your idea seems the right one to me:

• load all 10.000.000 items from the db in one go
• save them all in the cache individually with a Set call for each of them (with a reasonable cache duration)

Then, when you need one of them during the lifetime of your application, call GetOrSet({id}, _ => GetValue(id)) so that if the value is still in the cache you'll get it back immediately and, if not in the cache anymore, it will be loaded from the db and saved in the cache.

There's this passage that I don't understand though:

But that just seems... a bit hacky to me as i neither want to get nor set the value, i just want to set the factory up

Why do you say it feels hacky? Just to be clear, you don't need to call GetOrSet for each item when you are prefetching the entire thing at the beginning, you only need to call GetOrSet later on when you need some of those values and, in that moment, the GetOrSet means "get me X from the cache and, if it is not there, load it and set it".

Maybe you are thinking about calling GetOrSet for each key in the initial prefetching phase? If that is the case, that is not necessary.

So, to recap:

• INITIAL PREFETCHING: load all items from db -> for each item call Set with a reasonable duration
• DURING YOUR NORMAL APP USAGE: call GetOrSet so that if the value is expired from the cache it will be loaded again

Doing it this way will allow you to have the cache already filled at start + automatically keep some of those items in the cache, based on actual usage.

Let me know if I got this right and if I can help you more.

Hope this helps.

from fusioncache.

ps: if you plan on also using a 2nd layer (distributed cache) keep in mind that the initial prefetching may not be necessary, since the data may already be in the distributed cache because of previous runs.

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I'm converting this into a discussion.

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