Can Cosmos SDK3 Container be a singleton?

Question

I would like to reduce load on Azure Cosmos DB SQL-API, which is called from a .NET Core Web API with dependency injection.

In App Insights, I have noticed that every call to the Web API results in GetDatabase and GetCollection calls to Cosmos which can take 5s to run when Cosmos is under heavy load.

I have made CosmosClient a singleton (e.g advice here - https://docs.microsoft.com/en-us/azure/cosmos-db/performance-tips-dotnet-sdk-v3-sql)

However I could not find any advice for whether the Database or Container objects could also be singletons so these are created for each request to the Web API.

I check for the existence of the database and collection (e.g. following advice here - https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.cosmosclient.getdatabase?view=azure-dotnet#remarks and https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.cosmosclient.getcontainer?view=azure-dotnet#remarks)

This means that for every request to the Web API, the following code is run

var databaseResponse = await this.cosmosClient.CreateDatabaseIfNotExistsAsync(
    this.databaseConfiguration.DatabaseName,
    throughput: this.databaseConfiguration.DatabaseLevelThroughput);
var database = databaseResponse.Database;
var containerResponse = await database.CreateContainerIfNotExistsAsync(containerId, partitionKey);
var container = containerResponse.Container;

Can I make Database and Container singletons and add them to the DI to be injected like CosmosClient in order to reduce the number of calls to GetDatabase and GetCollection seen in App Insights?

CallMeWhy CallMeWhy · Accepted Answer · 2020-06-15T09:44:53

CreateDatabaseIfNotExistsAsync should only be called once as it is just a setup step for DB configuration.

You'd better create a DbService to persist the container object. And inject the DbService into each services instead of the DB client

Can Cosmos SDK3 Container be a singleton?

2 Answers