Update circuitbreaker.md #32556
Update circuitbreaker.md #32556
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Hi @azarboon, Thank you for your contribution! We really value the time you've taken to put this together. Before we proceed with reviewing this pull request, please sign the Lightbend Contributors License Agreement: |
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| @@ -24,6 +24,8 @@ resource exhaustion. Circuit breakers can also allow savvy developers to mark p | |||
| the site that use the functionality unavailable, or perhaps show some cached content as | |||
| appropriate while the breaker is open. | |||
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| Like any other pattern, circuit breakers have their own challenges: circuit breakers can misinterpret a partial failure as total system failure and inadvertently bring down the entire system. In particular, sharded systems and cell-based architectures are vulnerable to this issue. For example, let’s say only one of your database shards is overloaded and other shards are working normally. Usually in such circumstances, the circuit breaker either assumes the entire database (i.e. all shards) is overloaded and trips which negatively impacts the normal shards, or the circuit breaker assumes the required threshold hasn’t been exceeded and doesn’t do anything to mitigate overloading of the problematic shard. In either case, the result is not optimal. A workaround is that the server indicates to the client exactly which specific part is overloaded and the client uses a corresponding mini circuit breaker. However, this workaround can be complex and expensive. | |||
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Thanks for you contribution @azarboon.
However, I don't think the added paragraph is helping understand Akka's circuit breakers.
The example that of a system being brought down doesn't seem to apply. If you have a distributed database, the access to the instances is managed by some connection pool + driver. The application itself won't be connecting to db shards individually.
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Fair enough. How about cell based architecture? May I change the example to that?
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I'm not sure. What is missing in the Akka documentation about Circuit Breakers that needs to be addressed?
It's good if we have a succinct, high-level, explanation about the concept of Circuit Breakers followed by how to use the Akka APIs.
But if the intro about Circuit Breakers is too extensive, then we miss the main goal. The are enough resources on the internet (articles, blogs, videos) about it and interested users will dig the web for more information.
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You are right. But the problem is that the problem I mentioned, is not well known. Marc Brooker has written an excellent post explaining this. But it's buried and not well-known. So, I'm attempting to evangelize it so builders can be informed. Given that Akka is a well-known resource, it would be great if it evangelizes about challenges of this pattern. I'm thinking maybe we can add a link to that post for further reading? This way we can keep the doc succinct while giving heads-up to builders. What's your advice?
This page mainly mentions benefits of the pattern. I've added some challenges so readers can take a more informed decision.
References #xxxx