PrestaShop Behind a Load Balancer: What Breaks and How to Fix It

PrestaShop on a single server is fine. PrestaShop behind a load balancer with auto-scaling nodes — that's where the fun begins. The framework was never built for this, and it shows.

I've been running a B2B store on PrestaShop for several years now. ~300k SKUs, hundreds of orders a day, auto-scaling on GCP. Here's what went wrong and how we dealt with it.

800 Queries Per Product Page. Yes, Really.

A single product page in PrestaShop fires about 800 SQL queries. A category listing — around 2,000. Not a bug. That's just PrestaShop being PrestaShop.

On one server you stick Redis in front of it and forget about it. On multiple nodes — not so simple.

Cache Desync Between Nodes

PrestaShop caches query results locally. Redis, Memcached, whatever — it's per-node.…