What is received by the Azure function?

You have an Azure Cosmos DB for NoSQL account.

The change feed is enabled on a container named invoice.

You create an Azure function that has a trigger on the change feed.

What is received by the Azure function?

A. all the properties of the updated items

B. only the partition key and the changed properties of the updated items

C. all the properties of the original items and the updated items

D. only the changed properties and the system-defined properties of the updated items

View Answer

Answer: A

Explanation:

According to the Azure Cosmos DB documentation12, the change feed is a persistent record of changes to a container in the order they occur. The change feed outputs the sorted list of documents that were changed in the order in which they were modified.

The Azure function that has a trigger on the change feed receives all the properties of the updated items2. The change feed does not include the original items or only the changed properties. The change feed also includes some system-defined properties such as _ts (the last modified timestamp) and _lsn (the logical sequence number)3. Therefore, the correct answer is:

A. all the properties of the updated items