A ₹49,999 laptop went live at ₹4,999

transcript

12:03. A laptop is live in the sale at 4,999 rupees. It should be 49,999. And 1,800 orders are already in.

The interviewer asks: can anyone still buy it after the fix? And what do you do about the 1,800? The candidate splits it. What engineering guarantees. What the business decides.

12:03:10. Merchandising inserts an emergency price. Emergency beats sale. From that commit, no order at 4,999. Checkout re-prices from the primary. About a second later, Redis and every pod's cache update. Within two or three seconds, browse shows 49,999 too.

The interviewer pushes. Even a shopper holding a quote from 12:02? Even them. A quote is just what we showed. The order re-prices now.

Now the 1,800 orders placed before the fix. The difference is 45,000 rupees a laptop. Honour every one? 8 point 1 crore rupees.

Why not cancel them automatically? It's obviously a mistake. Then you've made a legal decision nobody signed off. Instead, every order line stores its price version. One query, exact list. And price history shows who set it, and when.

Honour or cancel is a business and legal call. Engineering's job is to make that decision easy.

Full breakdown in the lecture.