←back to thread

Caching is an abstraction, not an optimization

(buttondown.com)
134 points samuel246 | 1 comments | 01 Jul 25 10:42 UTC | HN request time: 0s | source
Show context
ckdot2 ◴[03 Jul 25 19:03 UTC] No.44458190[source]▶
"I think now caching is probably best understood as a tool for making software simpler" - that's cute. Caching might be beneficial for many cases, but if it doesn't do one thing then this is simplifying software. There's that famous quote "There are only two hard things in Computer Science: cache invalidation and naming things.", and, sure, it's a bit ironical, but there's some truth in there.
replies(11): >>44458265 #>>44458365 #>>44458502 #>>44459091 #>>44459123 #>>44459372 #>>44459490 #>>44459654 #>>44459905 #>>44460039 #>>44460321 #
EGreg ◴[03 Jul 25 19:41 UTC] No.44458502[source]▶
I never understood about cache invalidation or naming things

Both are not that difficult, honestly.

Aren’t there a lot harder things out there

replies(8): >>44458592 #>>44458650 #>>44458692 #>>44458868 #>>44458913 #>>44459031 #>>44459481 #>>44459828 #
1. TOGoS ◴[03 Jul 25 21:53 UTC] No.44459481[source]▶
There is a secret technique, called content-addressing[1], which elegantly solves both of them at once.

A lot of people haven't caught on, and try to cache things using ambiguous names, hence the struggle to invalidate their caches when the meaning changes.

[1] This can be applied even if you don't know the content yet; you just have to unambiguously name the inputs to the function that produces it. You might not know what all the inputs are, and then you have to start adding stuff like "unknown-unknown-2025-07-03T16", but it'll still basically work.