One Pager Cheat Sheet

• We will learn about the architecture and algorithms behind Facebook's newsfeed system in this lesson.
• Facebook's Newsfeed provides users with personalized information and updates relevant to them based on connections they have made with other users on the platform.
• The user's post is processed and sent through the web server to the application servers and the back-end to generate a newsfeed, which is then stored and sent to the user through feed notifications.
• At the database level, the most important entity in the system design of a newsfeed system is the user, who will be assigned a unique ID along with a feed item, feed and feed_id, which corresponds to different media sources and is linked by two main relationships between user - user and feed item - media.
• Newsfeed systems are typically represented using relational databases, where tables are linked through foreign keys to form relationships between entities.
• The ranking algorithm sorts and ranks the feed items queried from the feed database according to recency and relevance for each user, and the generated feed can be stored in a cache memory for faster retrieval of content and better user experience.
• Feed publishing is the process of displaying data to each specific user, and it can be processed by push, pull, or a hybrid model to reduce resource usage while maintaining performance.
• Facebook's edge rank algorithm assigns a rank to each feed item based on Affinity, Weight, and Decay, and users are then presented their feed items in order of relevance.
• Fan-out-on-load is a process used to cache the feed of a user to the user's device, thus increasing the efficiency of the newsfeed publishing process without increasing the write operations when publishing.
• The core technologies of the Facebook newsfeed system remain unchanged despite its constant updates and changes for optimization.