4 ms·
"If we don't need performance, we don't need caches" feels like a great broader takeaway here.
by lemagedurage 1y ago
"If we don't need performance, we don't need caches" feels like a great broader takeaway here.
- motorest 1y ago> "If we don't need performance, we don't need caches" feels like a great broader takeaway here. I don't think this holds true. Caches are used for reasons other than performance. For example, caches are used in some scenarios for stampede protection to mitigate DoS attacks. Also, the impact of caches on performance is sometimes negative. With distributed caching, each match and put require a network request. Even when those calls don't leave a data center, they do cost far more than just reading a variable from memory. I already had the displeasure of stumbling upon a few scenarios where cache was prescribed in a cargo cult way and without any data backing up the assertion, and when we took a look at traces it was evident that the bottleneck was actually the cache itself.
- ralegh 1y agoDoS is a performance problem, if your server was infinitely fast with infinite storage they wouldnt be an issue.
- lomase 1y agoIf my gandma had wheels it would be a car.
- indymike 1y agoIt is actually a financial problem too. Servers stop working when the bill goes unpaid. Sad but true.
- motorest 1y ago> DoS is a performance problem Not really. Running out of computational resources to fulfill requests is not a performance issue. Think of thinks such as exhausting a connection pool. More often than not, some components of a system can't scale horizontally.
- IanCal 1y agoA cache being fast enough doesn’t mean no caching is relevant - I’m not sure why you’d equate the two.
- hobs 1y agoI see people downvoting this. Anyone who disagrees with this, we have YAGNI for a reason - if someone said to me my performance was fine and they added caches, I would look at them with a big hairy eyeball because we already know cache invalidation is a PITA, that correctness issues are easy to create, and now you have the performance of two different systems to manage. Amazon actually moved away from caches for some parts of its system because consistent behavior is a feature, because what happens if your cache has problems and the interaction between that and your normal thing is slow? What if your cache has some bugs or edge case behavior? If you don't need it you are just doing a bunch of extra work to make sure things are in sync.
- indymike 1y agoSometimes, a cache is all about reducing expense: I.e, free cache query vs expensive API query.
- amluto 1y agoSometimes people host software on a server they own or rent, the server is plenty fast, and it costs literally nothing to issue those queries at the scale on which they’re needed.
- indymike 1y agoYes, that is true, but the original poster said getting rid of caches was always a good idea, when in reality the answer (as usual with engineering) is “it depends.”