Specify a default TTL on a container for a transactional store

To specify a default Time-To-Live (TTL) on a container for a transactional store in Microsoft Azure Cosmos DB, you can leverage the Cosmos DB SDKs or the Azure portal. This article will guide you through the process of implementing the default TTL on a container using both approaches.

Default TTL allows you to define a time duration in seconds for the documents in a container to live. Once this duration elapses, Cosmos DB automatically removes the expired documents from the container. This feature is especially useful for scenarios where you need to store time-sensitive data or implement data retention policies.

Using Cosmos DB SDKs

1. Ensure you have the necessary Cosmos DB SDK installed in your application. You can find the SDKs and their installation instructions from the official Azure Cosmos DB SDKs page.
2. Create an instance of the CosmosClient class, which represents the Cosmos DB account connection. You’ll need to provide the account endpoint URI and the account key or another appropriate authentication method. For example:
   using Microsoft.Azure.Cosmos;

   // ...

   string endpointUri = "";
   string accountKey = "";

   CosmosClient cosmosClient = new CosmosClient(endpointUri, accountKey);


3. Retrieve the container where you want to set the default TTL using the GetContainer method, specifying the database ID and the container ID. For example:
   string databaseId = "";
   string containerId = "";

   Database database = cosmosClient.GetDatabase(databaseId);
Container container = database.GetContainer(containerId);


4. To set the default TTL on the container, you can use the ReplaceContainerAsync method and provide the modified container properties, including the DefaultTimeToLive property. For example:
   ContainerProperties containerProperties = await container.ReadContainerAsync();
   containerProperties.DefaultTimeToLive = 3600; // TTL set to 1 hour

   await container.ReplaceContainerAsync(containerProperties);

By setting the DefaultTimeToLive property to 3600 (1 hour), all documents that you insert into this container will have a default TTL of 1 hour, unless you specify a different value at the document level.

Using the Azure portal

1. Navigate to the Azure portal and open your Cosmos DB account.
2. In the left-hand menu, click on “Data Explorer.”
3. Select the appropriate database and container from the tree view.
4. In the container view, click on the “Settings” tab.
5. Under “Time to Live (TTL),” check the “Enable” box to enable the TTL feature.
6. Set the desired TTL duration (in seconds) in the “Default time to live (seconds)” input box.
7. Click the “Save” button to apply the changes.

Once you have done this, the container will automatically remove documents that have expired based on the time duration you specified in the default TTL.

In this article, we have discussed how to specify a default TTL on a container for a transactional store in Azure Cosmos DB. Whether you prefer using the Cosmos DB SDKs or the Azure portal, you can easily implement default TTL to automatically manage the lifecycle of your data in a container.