A comprehensive analysis of Azure Cosmos DB Change Feed: A guide to real-time data processing and event-driven computing

What is Azure Cosmos DB Change Feed?

Azure Cosmos DB Change Feed is a persistent record used to track all changes occurring in a container. Change Feed supports listening to any changes in a container within Azure Cosmos DB and outputs a list of documents arranged in order of modification. These changes can be processed asynchronously and incrementally, and the output can be distributed to one or more consumers for parallel processing.

Functions of Change Feed

1. Real-time Data Processing: Change Feed can be used for real-time data processing, such as real-time analysis of operational data in Internet of Things (IoT) applications.
2. Event-driven Computing: Change Feed can be used to trigger notifications or invoke APIs when data changes occur in the container.
3. Data Synchronization: Change Feed can be used to synchronize data to caches, search engines, data warehouses, or cold storage.
4. Data Migration: Change Feed can be used to migrate data from the production environment to other systems.

How to Use Change Feed

1. Connecting to Change Feed: You can connect to Change Feed using the Azure Cosmos DB SDK to fetch changes in the container.
2. Configuring Change Feed Modes: Azure Cosmos DB provides two Change Feed modes: Latest Version Mode and All Versions and Deletes Mode (preview). You can choose the appropriate mode based on your needs.
3. Processing Changes: You can use Azure Functions or Change Feed Processor to handle changes, automatically retrieve changes in the container, and perform corresponding operations.