Azure Series : Cosmos DB : Enhancing Query Performance with Azure Cosmos DB Indexing in .NET Core: Practical Code and Data Examples

 In modern applications, query performance is crucial for providing a seamless user experience. Azure Cosmos DB, a globally distributed NoSQL database service, offers indexing capabilities to optimize query performance. In this article, we will explore practical code and data examples of how to leverage Azure Cosmos DB indexing in .NET Core applications to enhance query performance.

Setting up the Environment

Before we begin, ensure you have the necessary prerequisites installed:

1. Visual Studio or Visual Studio Code with the .NET Core SDK.
2. Azure Cosmos DB account and connection string.

Step 1: Create a .NET Core Project

Open Visual Studio or Visual Studio Code and create a new .NET Core project. Select the appropriate project template based on your application's needs.

Step 2: Install Azure Cosmos DB NuGet Package

In the NuGet Package Manager Console, install the official Azure Cosmos DB SDK for .NET Core:

Install-Package Microsoft.Azure.Cosmos

Step 3: Connect to Azure Cosmos DB

In your .NET Core application, establish a connection to your Azure Cosmos DB account using the CosmosClient class:

using Microsoft.Azure.Cosmos;

const string cosmosDbConnectionString = "YOUR_CONNECTION_STRING";
CosmosClient cosmosClient = new CosmosClient(cosmosDbConnectionString);

Step 4: Define and Configure Indexing Policies

Decide whether you want to use Automatic Indexing or Manual Indexing. For Manual Indexing, define and configure the indexing policy for your container:

// Define the indexing policy
IndexingPolicy indexingPolicy = new IndexingPolicy
{
    Automatic = false, // Set to true for automatic indexing
    IndexingMode = IndexingMode.Consistent,
    IncludedPaths = new Collection<IncludedPath>
    {
        new IncludedPath
        {
            Path = "/*" // All properties will be indexed
        }
    }
};

// Create or retrieve the container and set the indexing policy
Database database = await cosmosClient.GetDatabase("YOUR_DATABASE_ID");
Container container = await database.GetContainer("YOUR_CONTAINER_ID");
await container.ReplaceContainerAsync(new ContainerProperties(container.Id, partitionKeyPath)
{
    IndexingPolicy = indexingPolicy
});

Step 5: Insert Sample Data

Insert some sample data into the container:

public class SampleData
{
    public string Id { get; set; }
    public string Name { get; set; }
    // Add more properties as needed
}

// Insert sample data into the container
SampleData data1 = new SampleData { Id = "1", Name = "John Doe" };
await container.CreateItemAsync(data1);

SampleData data2 = new SampleData { Id = "2", Name = "Jane Smith" };
await container.CreateItemAsync(data2);

Step 6: Execute Queries with Indexing

Now, let's execute some queries using the indexing strategy:

// Query for items with a specific Name property
string query = "SELECT * FROM c WHERE c.Name = @name";
QueryDefinition queryDefinition = new QueryDefinition(query).WithParameter("@name", "John Doe");

FeedIterator<SampleData> queryResultSetIterator = container.GetItemQueryIterator<SampleData>(
    queryDefinition, requestOptions: new QueryRequestOptions { PartitionKey = new PartitionKey("YOUR_PARTITION_KEY_VALUE") });

List<SampleData> results = new List<SampleData>();
while (queryResultSetIterator.HasMoreResults)
{
    FeedResponse<SampleData> response = await queryResultSetIterator.ReadNextAsync();
    results.AddRange(response.Resource);
}

// Process the results as needed

Azure Cosmos DB indexing is a powerful tool to optimize query performance in .NET Core applications. By strategically using indexes, you can reduce data retrieval times, minimize resource consumption, and improve overall application responsiveness. The code and data examples presented in this article demonstrate how to connect to Azure Cosmos DB, define indexing policies, insert sample data, and execute queries using the indexing strategy. Incorporate these practices into your .NET Core applications to leverage the full potential of Azure Cosmos DB and deliver an exceptional user experience.