Change Feed
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Category: Integration & Analytics
Summary: Persistent, ordered log of item inserts/updates, consumable by apps and Azure Functions.
Overview
The change feed is a persistent, ordered log of changes (inserts and updates) made to items within an Azure Cosmos DB container, available for consumption by applications, Azure Functions, or other Azure services. It is a foundational building block for scenarios such as event-driven architectures, real-time analytics, denormalization, referential integrity enforcement, aggregation, and data archiving.
Container monitoredContainer =
database.GetContainer("Orders");
Container leaseContainer =
database.GetContainer("Leases");
ChangeFeedProcessor processor =
monitoredContainer
.GetChangeFeedProcessorBuilder(
processorName: "orders-processor",
onChangesDelegate: HandleChangesAsync)
.WithLeaseContainer(leaseContainer)
.Build();
More Info & Links
DP-420 Style Practice Questions
Q1. What does the Azure Cosmos DB change feed provide?
- A. A persistent, ordered log of insert/update operations on container items
- B. A one-time export of all data in a container
- C. A record of only delete operations
- D. A backup of the entire database account
Q2. Which of these is a common use case for the change feed?
- A. Denormalizing data or enforcing referential integrity via Azure Functions
- B. Defining the container's partition key
- C. Encrypting data at rest
- D. Configuring the consistency level
Answer Key
Answers are listed at the very end so you can attempt the questions first.
- Q1 (Change Feed): A. A persistent, ordered log of insert/update operations on container items — The change feed captures inserts and updates (not deletes, by default) as an ordered, persistent log for downstream consumption.
- Q2 (Change Feed): A. Denormalizing data or enforcing referential integrity via Azure Functions — Change feed + Azure Functions is commonly used for denormalization, referential integrity, aggregation, and archiving.
DP-420: Designing and Implementing Cloud-Native Applications Using Microsoft Azure Cosmos DB — term detail page
