Why does a MYSQL query live so little in the cache?

Question

MySQL

I have a very long request, it takes about two seconds.

How is it happening.

I refresh the page for the first time - this request is loaded in 2 seconds.
I update the second time, the result is taken from the cache, and it is already running for 0.05-0.1 seconds.

After 5 minutes, nothing, absolutely nothing in the database changes. But when the page is refreshed, the request again takes 2 seconds.

How can I make the cache lifetime increase to several hours, or so that it is reset only when the specific table, to which the request was made, changes

Answer 1

the muscle will overwrite the old values ​​when the cache is full.
increase the cache size or use third-party caching.
the muscle cache is deprecated and will soon be gone in the engine
, there are alternative approaches. for example, query optimization. so that there is no need for caching at all. More precisely, this is the main recipe.

Answer 2

1. Optimize a long query.
2. Use caching in the application with the desired lifetime.