How to configure the Azure Cosmos DB integrated cache

APPLIES TO: NoSQL

This article describes how to provision a dedicated gateway, configure the integrated cache, and connect your application.

Prerequisites

• If you don't have an Azure subscription, create a free account before you begin.
• An existing application that uses Azure Cosmos DB. If you don't have one, here are some examples.
• An existing Azure Cosmos DB API for NoSQL account.

Provision the dedicated gateway

1. Navigate to an Azure Cosmos DB account in the Azure portal and select the Dedicated Gateway tab.

   

2. Fill out the Dedicated gateway form with the following details:

   • Dedicated Gateway - Turn on the toggle to Provisioned.
   • SKU - Select a SKU with the required compute and memory size. The integrated cache will use approximately 50% of the memory, and the remaining memory is used for metadata and routing requests to the backend partitions.
   • Number of instances - Number of nodes. For development purpose, we recommend starting with one node of the D4 size. Based on the amount of data you need to cache and to achieve high availability, you can increase the node size after initial testing.

   

3. Select Save and wait about 5-10 minutes for the dedicated gateway provisioning to complete. When the provisioning is done, you'll see the following notification:

   

Configuring the integrated cache

When you create a dedicated gateway, an integrated cache is automatically provisioned.

1. Modify your application's connection string to use the new dedicated gateway endpoint.

   The updated dedicated gateway connection string is in the Keys blade:

   

   All dedicated gateway connection strings follow the same pattern. Remove documents.azure.com from your original connection string and replace it with sqlx.cosmos.azure.com. A dedicated gateway will always have the same connection string, even if you remove and reprovision it.

   You don’t need to modify the connection string in all applications using the same Azure Cosmos DB account. For example, you could have one CosmosClient connect using gateway mode and the dedicated gateway endpoint while another CosmosClient uses direct mode. In other words, adding a dedicated gateway doesn't impact the existing ways of connecting to Azure Cosmos DB.

2. If you're using the .NET or Java SDK, set the connection mode to gateway mode. This step isn't necessary for the Python and Node.js SDKs since they don't have additional options of connecting besides gateway mode.

Note

If you are using the latest .NET or Java SDK version, the default connection mode is direct mode. In order to use the integrated cache, you must override this default.

Adjust request consistency

You must ensure the request consistency is session or eventual. If not, the request will always bypass the integrated cache. The easiest way to configure a specific consistency for all read operations is to set it at the account-level. You can also configure consistency at the request-level, which is recommended if you only want a subset of your reads to utilize the integrated cache.

Note

If you are using the Python SDK, you must explicitly set the consistency level for each request. The default account-level setting will not automatically apply.

Adjust MaxIntegratedCacheStaleness

Configure MaxIntegratedCacheStaleness, which is the maximum time in which you are willing to tolerate stale cached data. It is recommended to set the MaxIntegratedCacheStaleness as high as possible because it will increase the likelihood that repeated point reads and queries can be cache hits. If you set MaxIntegratedCacheStaleness to 0, your read request will never use the integrated cache, regardless of the consistency level. When not configured, the default MaxIntegratedCacheStaleness is 5 minutes.

Note

The MaxIntegratedCacheStaleness can be set as high as 10 years. In practice, this value is the maximum staleness and the cache may be reset sooner due to node restarts which may occur.

Adjusting the MaxIntegratedCacheStaleness is supported in these versions of each SDK:

SDK	Supported versions
.NET SDK v3	>= 3.30.0
Java SDK v4	>= 4.34.0
Node.js SDK	>=3.17.0
Python SDK	>=4.3.1

.NET

FeedIterator<MyClass> myQuery = container.GetItemQueryIterator<MyClass>(new QueryDefinition("SELECT * FROM c"), requestOptions: new QueryRequestOptions
        {
            DedicatedGatewayRequestOptions = new DedicatedGatewayRequestOptions 
            { 
                MaxIntegratedCacheStaleness = TimeSpan.FromMinutes(30) 
            }
        }
);

Java

DedicatedGatewayRequestOptions dgOptions = new DedicatedGatewayRequestOptions()
   .setMaxIntegratedCacheStaleness(Duration.ofMinutes(30));
CosmosQueryRequestOptions queryOptions = new CosmosQueryRequestOptions()
   .setDedicatedGatewayRequestOptions(dgOptions);

CosmosPagedFlux<MyClass> pagedFluxResponse = container.queryItems(
        "SELECT * FROM c", queryOptions, MyClass.class);

Node.js

 const queryRequestOptions = {
   maxIntegratedCacheStalenessInMs: 1800000 };
 const querySpec = {
   query: "SELECT * from c"
 };
 const { resources: items } = await container.items
   .query(querySpec, queryRequestOptions)
   .fetchAll();

Python

query = "SELECT * FROM c"
container.query_items(
    query=query,
    max_integrated_cache_staleness_in_ms=1800000
)

Verify cache hits

Finally, you can restart your application and verify integrated cache hits for repeated point reads or queries by seeing if the request charge is 0. Once you’ve modified your CosmosClient to use the dedicated gateway endpoint, all requests will be routed through the dedicated gateway.

For a read request (point read or query) to utilize the integrated cache, all of the following criteria must be true:

• Your client connects to the dedicated gateway endpoint
• Your client uses gateway mode (Python and Node.js SDKs always use gateway mode)
• The consistency for the request must be set to session or eventual

Note

Do you have any feedback about the integrated cache? We want to hear it! Feel free to share feedback directly with the Azure Cosmos DB engineering team: cosmoscachefeedback@microsoft.com

Next steps

• Integrated cache FAQ
• Integrated cache overview
• Dedicated gateway