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Comment by taylor-s | Hacker News Reader

Retries are good, conditional on having a client-side circuit breaker that stops retries quickly when nothing is working. Otherwise, they are good in good times and bad in bad times.

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Retries without (exponential) backoff and/or circuit breakers are almost universally bad, and can even prevent a service from recovering.

Source: decades of operational pain.

This is one of the scenarios where I feel we as engineers should have been more diligent in publicly writing down what techniques have worked in which scenarios and what haven't, and the AI could have gathered decades of operational knowledge and provide proper guidance to architects designing new systems. It's also true that we're witnessing unprecedented levels of scale.

Thundering herds and circuit breakers are extremely well documented and practiced in production. AI absolutely knows about this.

But knowing when to use which strategy and when a simple retry suffices is precisely the type of thing humans will remain to be better at than AI for the foreseeable future.

I think the “thundering herd” problem is pretty extensively documented

Don't forget jitter as well. Otherwise your clients will just coordinate their retries.

isn't that a bomb with a pair of scissors to cut the fuse that could break down under certain conditions?

I feel like they could also hide an issue that might get fixed if there were no retries. Is it slow or is our resource sporadically offline?

Exponential back off retries could hide a real issue, but I would estimate something like 99.99999999% of network retries are resolved within the first 2 attempts.

Not using retries is optimizing for the astronomically rare case, which is better mitigated by other means

Google “thundering herd” and you’ll understand why uncontrolled retries can be / are bad.

Quarrelsome is suggesting you should have no retries, not unlimited.

Yes I’m aware, and they’re probably suggesting that something on a higher level should instead retry, and I’m arguing that you need to coordinate the retry mechanisms and behavior between differently layers of your stack.

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