Flash Sale: System Definition

Step 1: System Definition

A flash sale system is the part of an e-commerce site that runs short sales events. A small stock of products is sold to a very large number of buyers in a short time. Traffic spikes the moment the sale opens. For example, hundreds of thousands of users may hit the site at the same time. Purchase requests far outnumber the items. There may be millions of requests for only thousands of units.

The system has three jobs. It must serve many users at once. It must track inventory reliably. It must hand out the items fairly.