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Faith Sithole
Faith Sithole

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The Great Scaling Stall of 2025: Configuration Decisions That Blew Us Away

The Problem We Were Actually Solving

Our Treasure Hunt Engine was built on a monolithic architecture with a single-threaded worker process handling all requests. The system would stall as soon as the incoming requests exceeded a certain threshold, taking down the entire service. This was not ideal, but it was the best we could do at the time. Our team prioritized speed of development over clean architecture, which turned out to be a costly decision.

What We Tried First (And Why It Failed)

We initially tried to add more instances of the worker process to our AWS autoscaling group in an attempt to distribute the load more evenly. However, this only led to more instances eventually hitting the same bottleneck, as the worker process was still single-threaded and unable to handle multiple concurrent requests efficiently. We were unaware of the concept of scalability bottlenecks at the time. Our attempts to scale horizontally without addressing the root cause of the issue only masked the symptoms and prolonged our efforts to find a solution.

The Architecture Decision

As we reflected on our architecture, we realized that the single-threaded worker process was the culprit behind our scaling woes. We were trying to scale a hammer when we needed to redesign our toolset. We decided to refactor the Treasure Hunt Engine to use a distributed, multi-threaded architecture with a message queue at its core. This would allow us to scale the system horizontally and handle incoming requests in a more efficient and clean manner.

What The Numbers Said After

After implementing the new architecture, our system was able to handle a peak load of 500 concurrent requests without stalling. This was a significant improvement over the previous monolithic architecture which would stall at around 50 concurrent requests. Our production operator reported a 90% reduction in downtime and a 75% increase in overall system efficiency. The numbers spoke for themselves; our newfound scalability was a game-changer for the Treasure Hunt Engine.

What I Would Do Differently

If I were to do it all over again, I would prioritize clean architecture from the very beginning. I would take the time to understand the scalability requirements of the system and design it accordingly. I would avoid the pitfalls of a single-threaded worker process and opt for a distributed architecture from the start. While our solution ultimately succeeded, it was a costly and time-consuming exercise that could have been avoided with a more careful and deliberate architectural approach.

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