Curriculum
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Module 3 · Lesson 2
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Queues and back-pressure
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Starter file missingLearners hit the code demo at 07:40 with nothing to run. This is where 60% of them leave.
Lesson description
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Write it as a capability, not a topic. "Explain why…" beats "Introduction to queues."
Knowledge check
2 questions · 70% to pass · unlimited retries
Q1A queue grows without bound. What actually breaks first?Single answer
The consumer's CPU
✓Producer memory — the queue is the leak
The network link
Nothing; queues are elastic
Explanation shown after answering: An unbounded queue doesn't fail loudly. It absorbs the backlog until the process running it runs out of memory — which is why the outage looks like the producer's fault.
Q2Which of these are valid back-pressure signals?Multiple
✓Blocking the producer's write call
✓Returning 429 with a retry-after
Silently dropping the oldest message
✓Reducing the producer's rate limit token bucket
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Release
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