W

Performance

66 articles

k61 min read

k6 — Load Testing Your API

Load test APIs with k6. Simulate traffic, measure performance, and identify bottlenecks.

Read →
backend6 min read

Auto-Scaling Gone Wrong — When Your Scaler Makes Things Worse

Auto-scaling is supposed to save you during traffic spikes. But misconfigured scalers can thrash (scaling up and down every few minutes), scale too slowly to help, or scale to so many instances they exhaust your database connection pool. Here''s how to tune auto-scaling to actually work.

Read →
backend6 min read

Blocking I/O in Async Systems — The Node.js Event Loop Killer

One synchronous, blocking operation in your Node.js server blocks EVERY concurrent request. JSON.parse on a 10MB payload, a for-loop over 100k items, or a synchronous file read — all of them freeze your event loop and make your entire server unresponsive. Here''s how to find and eliminate blocking I/O.

Read →
backend6 min read

Cache Stampede — When Your Cache Fix Breaks Everything

Cache stampede (a.k.a. thundering herd on TTL expiry) is one of the most dangerous failure modes in high-traffic systems. The moment your cache key expires, hundreds of simultaneous requests hammer your database — often killing it. Here''s how it happens, and exactly how to fix it.

Read →
backend6 min read

Load Balancer Misconfiguration — The Hidden Single Point of Failure

A misconfigured load balancer can route all traffic to one server while others idle, drop connections silently, or fail to detect unhealthy backends. These problems are invisible until they cause production incidents. Here are the most dangerous LB misconfigurations and how to fix them.

Read →
backend6 min read

Memory Leak in Production — How to Find and Fix It

Memory leaks in Node.js are insidious — your service starts fine, runs smoothly for hours, then slowly dies as RAM fills up. Every restart buys a few more hours. Here''s how to diagnose, profile, and permanently fix memory leaks in production Node.js applications.

Read →
backend6 min read

N+1 Query Problem — The Silent Performance Killer in Every ORM

The N+1 query problem is responsible for more "why is my app slow?" investigations than almost anything else. It hides perfectly in development, then silently kills your database at scale. Here''s exactly what it is, how to detect it, and every way to fix it.

Read →
backend6 min read

Redis Eviction Causing Chaos — When Your Cache Turns on You

Redis is full. Instead of failing gracefully, it starts silently evicting your most important cache keys — session tokens, rate limit counters, distributed locks. Your app behaves mysteriously until you realize Redis has been quietly deleting data. Here''s how to tame Redis eviction.

Read →
backend6 min read

Slow Queries That Only Appear at Scale — The Indexing Problem

Your query runs in 2ms in development with 1,000 rows. In production with 10 million rows, the same query takes 8 seconds. The database does a full table scan on every single request. Here''s how to identify missing indexes, write efficient queries, and build a database that stays fast as data grows.

Read →
backend6 min read

Thread Pool Starvation — Why Node.js Blocks Even in Async Code

You wrote perfectly async Node.js code — no blocking I/O, no synchronous loops. Yet under load, responses stall and CPU pegs. The culprit is Node.js''s hidden libuv thread pool being exhausted by crypto, file system, and DNS operations. Here''s what''s really happening.

Read →
python4 min read

Python Async/Await - Write Non-Blocking Code Like a Pro

Async programming in Python is no longer just for experts. With asyncio, async/await syntax, and modern libraries like httpx and aiofiles, you can write highly performant, non-blocking Python code with ease. Here's your complete guide.

Read →