A e-commerce website aims to provide a fast and easy-to-use purchase history for its customers, but faces challenges in scaling its index due to the large number of users and frequent updates. To address this, the website considers using a dynamic search index that is populated with user-specific data when the user logs in and expires after a certain time. This approach allows for efficient searching within each user's purchase history without maintaining a massive global index. The Redis Search and Query feature can be leveraged to create such indexes, which are ephemeral and can be easily managed and scaled.