A real-world case study of rescuing an enterprise e-commerce platform from performance hell, complete with war room panic, 63 SQL queries per page load, and the joy of watching response times drop from 15 seconds to under 700 milliseconds.
TL;DR - What Saved Us
The quick wins that took us from "users are leaving" to "users are buying":
- Killed N+1 queries - 63 database calls per page became 1
- Added composite indexes - The right indexes, in the right order
- Introduced caching layers - Redis for sessions and hot data
- Implemented async/await properly - Stopped blocking threads
- Broke the monolith strategically - Started with the checkout path
- Moved to read replicas - Separated reads from writes
Total impact: 15-second page loads → under 700ms. Cart abandonment dropped 34%.
The Call That Changed Everything
It was 6 PM on a Friday. My phone rang.
"The site is dying. Black Friday is in three weeks. We need you tomorrow."
The company? Let's call them MegaRetail. They had an e-commerce platform serving 2 million customers. It was built in 2009, survived a decade of "quick fixes," and was now buckling under its own weight. Page loads had crept up to 15 seconds. Cart abandonment was at 78%. Their biggest sales event of the year was approaching, and the system couldn't handle normal traffic, let alone Black Friday volumes.
I said yes. Because apparently I hate weekends.
What followed was four months of the most intense performance work I've done. This is that story.