System Design: Designing a Trending Feature

Question

Design the backend system for a top N trending topics feature.

Background

Similar to previous system design questions, this question is ambiguous and open-ended. It also involves streaming data, which is a nice tie-in with the previous question.

Solution Approach

We’ll follow the same approach as we did for the previous question:

• Define system requirements:

  Before we begin any design, we’ll spend a few minutes agreeing on the one to two primary use cases you’ll need to cover.

• System breakdown:

  We’ll then diagram the key individual components of the system needed to address the one to two primary use cases.

• Dataflow discussion:

  We’ll discuss the necessary data points the system will need to collect and how they flow through the system.

• Scaling the design:

  We’ll talk about design choices and trade-offs to ensure that the system scales.

• Capacity modeling:

  We’ll estimate the request volume and data volume the system will need to handle for a given time period.