What is the best practice in caching? What are the limits?

Question

Im using Zend_cache to cache results of some complicated db queries, services etc.

My site is social, that means that there is a lot of user interaction.

Im able to cache users data here and there as well. But taht means, that i will have nearly tens of thousands cache files (with 10 000 users). Is this approach to cache almost everything coming from db still good for performance? Or there are some limits of filesystem?

Was looking for some article around, didnt find.

Thanks for an advice! Jaroušek

Basically, you are wanting to know if the operations to look up, find, and open a cached file will actually hurt performance? — Levi Morrison, Oct 27 '11 at 14:59
Why do you think about file system limits? Zend_Cache is just proxy for external or internal cache system, you can use Redis/Memcache instead of files for caching. — Ilia Kondrashov, Oct 27 '11 at 15:20

score 5 · Answer 1 · answered Oct 27 '11 at 15:21

The question you should be asking is if the overhead of creating/populating/maintaining that cache exceeds the cost of generating the cacheable data in the first place.

If it costs you $1 to generate some data, $10 to cache it, and $0.8 to retrieve from cache, then you'd have to be able to retrieve that data from cache 50 times to break even.

If you only access the cached data 10 times before it expires/invalidates, then you're losing $8.

What is the best practice in caching? What are the limits?

1 Answers1