# Tag

Optimization

8 essays

Learning PathJun 20, 2026

When Your Threads Start Eating Your Server: Understanding Thread Pools Beyond The Hype

Another late night debugging a thrashing service? This is a debrief on why thread pools exist, when they actually save your ass in production, and the ugly truths you'll learn when you inevitably get them wrong.

Youssef El Hejjioui·9 min
Systems Optimization & Performance EngineeringJun 11, 2026

The Living Dead: Why Java Feels So Exhausting Now

After another night battling a production incident fueled by Java's 'enterprise-grade' complexity, it's time to admit: Java isn't dead, it's the undead zombie in our server rooms, a costly and exhausting relic.

Youssef El Hejjioui·7 min
Systems Optimization & Performance EngineeringMay 22, 2026

RabbitMQ vs. Kafka: When the Diagrams Lie and Prod Explodes

Another 3 AM call, another 'why is this broken?' moment. Let's talk about RabbitMQ and Kafka not from some clean architecture diagram, but from the trenches where message queues and event streams either save your ass or become the reason you're looking for a new job.

Youssef El Hejjioui·5 min
Systems Optimization & Performance EngineeringMay 20, 2026

The Notification Grind: Go, Node, and RabbitMQ in Multi-Tenant Hell

Remember that Tuesday at 2 AM? The one where a minor tenant's custom webhook brought down notification delivery for everyone? Yeah. We ended up deep in the trenches, comparing Go and Node.js for a critical RabbitMQ-backed service.

Youssef El Hejjioui·8 min
Systems Optimization & Performance EngineeringMay 19, 2026

Cutting Through the Noise: A Late-Night Rant on Directness in Systems

Another 3 AM production incident survived. Time to talk about why we make our systems so damn complicated, and why sometimes, the most elegant solution is the one that just gets straight to the point.

Youssef El Hejjioui·6 min
Systems Optimization & Performance EngineeringMay 18, 2026

AI Coding Assistants Fail at Production Debugging

AI coding assistants generate correct-looking code but often fail in production debugging. Learn why runtime profiling, system constraints, and execution paths matter more than generated solutions.

Youssef El Hejjioui·3 min
Systems Optimization & Performance EngineeringMay 14, 2026

From 500ms to 900ms: How AI-Assisted “Optimizations” Turned a Fast Query into a Slow One — and What Brought It Back to 43ms

An API endpoint went from 500ms to 900ms after AI-suggested “optimizations,” until removing ORM abstraction and switching to raw SQL reduced it to 43ms, revealing how performance depends more on system understanding than generated fixes.

Youssef El Hejjioui·5 min
Systems Optimization & Performance EngineeringMay 14, 2026

It worked on localhost. Obviously.

Localhost is a comfortable, consequence-free fantasy. Production is where software goes to find out what it actually is. A 3am field report from someone who has been profiling things nobody asked them to profile.

Youssef El Hejjioui
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