How do I bulk delete documents in Cosmos DB?

You can bulk delete documents in Cosmos DB using a variety of methods:

• Stored Procedures: Write a stored procedure that iterates through a set of documents and deletes them. This is useful when you need to delete documents based on specific criteria or perform conditional deletes.
• Bulk Executor Library: Use the Bulk Executor Library for .NET, which offers a bulk delete feature to efficiently remove large numbers of documents. This library optimizes throughput consumption and speeds up the process.
• Azure Data Factory (ADF): Utilize ADF to create a pipeline that bulk deletes documents. ADF allows you to define the deletion logic and parameters for your pipeline.
• Time To Live (TTL): Set a TTL property for your container's items. By setting it to a short duration, Cosmos DB automatically deletes all items in the container after the specified time.

Example using a Stored Procedure:

// Sample Stored Procedure
function BulkDelete(partitionKey) {
    var collection = getContext().getCollection();
    var querySpec = {
        query: 'SELECT * FROM c WHERE c.partitionKey = @partitionKey',
        parameters: [{ name: '@partitionKey', value: partitionKey }]
    };
    var continuation = null;
    while (true) {
        var results = collection.queryDocuments(querySpec, continuation);
        continuation = results.continuationToken;
        if (results.results) {
            results.results.forEach(function (document) {
                collection.deleteDocument(document._self);
            });
        }
        if (!continuation) {
            break;
        }
    }
}

Note: Each method offers specific advantages depending on your needs and the size of the data you are deleting. Research and choose the most suitable approach for your use case.