4 ms·

Queues aren't really the problem here. It's that the people making changes don't have a decent understanding of the system they are trying to fix. If you don't

by jmull 3y ago

Queues aren't really the problem here. It's that the people making changes don't have a decent understanding of the system they are trying to fix. If you don't actually know what the problem is, your fix is not likely to work. I have seen groups put huge amounts of work into a "fix" for a system when they are only really guessing at what the problem is. (Besides queues, people also seem to like adding "caches" -- often stateful and with no validation strategy so not really caches -- or really any kind of wrapper or shim.) I think it is really useful to raise awareness of this kind of thing, but I think the article could put it a little better. For one thing, queues can "fix overload" depending on what you mean by that. They don't increase system capacity but can let a system handle bursty usage better.

sethammons 3y ago
Ran into this at work last week. A team wanted to add an in-mem cache to speed things up. However, they have no way nor plan to measure its effectiveness. I asked how they will know the cache hit ratio or otherwise know how the queue is working and they pushed back that such monitoring would be work they weren't planning. Bananas.
john-tells-all 3y ago
Strong agree. Caches can be horrible: - adds complexity of code and architecture - adds run-time complexity, with new failure modes - adds semi-random delays - see also: Buffer Bloat There's a reason it's one of the Two Hard Problems in Computer Science! https://martinfowler.com/bliki/TwoHardThings.html https://martinfowler.com/bliki/TwoHardThings.html
taneq 3y ago
> I have seen groups put huge amounts of work into a "fix" for a system when they are only really guessing at what the problem is. This is sadly far more the rule than the exception. So many times I've heard "we think the problem is [wild-ass guess] and so we're going to do [lengthy re-write] to fix it." And when I say "hey uh maybe we could do [simple test] to prove whether [wild-ass guess] is actually happening?" it's "oh no we can't waste time we have to start the rewrite" or even just "huh, yeah I guess we could test it that way, anyway... we start the rewrite tomorrow". Edit: one specific case I remember talking to a mechanical engineer about how a particular mass-spring system would react to a momentary impulse and he said "well there's no way to know what'll happen so let's just try it." Thinking back I can rationalise this answer as "we don't fully understand the dynamics of the piece of third-party equipment generating the impulse so let's just use this as a starting point" but at the time it made me so mad. Like, if only there were a discipline entirely dedicated to using mathematical modeling techniques to predict the behaviour of physical systems in order to back-calculate the necessary physical parameters to achieve a given behaviour.

by jmull 3y ago

sethammons 3y ago

Ran into this at work last week. A team wanted to add an in-mem cache to speed things up. However, they have no way nor plan to measure its effectiveness. I asked how they will know the cache hit ratio or otherwise know how the queue is working and they pushed back that such monitoring would be work they weren't planning. Bananas.

john-tells-all 3y ago

Strong agree. Caches can be horrible: - adds complexity of code and architecture - adds run-time complexity, with new failure modes - adds semi-random delays - see also: Buffer Bloat There's a reason it's one of the Two Hard Problems in Computer Science! https://martinfowler.com/bliki/TwoHardThings.html https://martinfowler.com/bliki/TwoHardThings.html

taneq 3y ago

> I have seen groups put huge amounts of work into a "fix" for a system when they are only really guessing at what the problem is. This is sadly far more the rule than the exception. So many times I've heard "we think the problem is [wild-ass guess] and so we're going to do [lengthy re-write] to fix it." And when I say "hey uh maybe we could do [simple test] to prove whether [wild-ass guess] is actually happening?" it's "oh no we can't waste time we have to start the rewrite" or even just "huh, yeah I guess we could test it that way, anyway... we start the rewrite tomorrow". Edit: one specific case I remember talking to a mechanical engineer about how a particular mass-spring system would react to a momentary impulse and he said "well there's no way to know what'll happen so let's just try it." Thinking back I can rationalise this answer as "we don't fully understand the dynamics of the piece of third-party equipment generating the impulse so let's just use this as a starting point" but at the time it made me so mad. Like, if only there were a discipline entirely dedicated to using mathematical modeling techniques to predict the behaviour of physical systems in order to back-calculate the necessary physical parameters to achieve a given behaviour.