Which API should be chosen to backup an object with large volumes (greater than 2 million) or to handle backup-related performance issues?

Choosing the Bulk API for backing up an object with large volumes of data, particularly those exceeding 2 million records, is highly suitable due to its design and capabilities tailored for processing large datasets efficiently. The Bulk API is specifically built for handling large amounts of data by allowing users to submit batches of records for processing asynchronously.

When working with significant volumes, the Bulk API optimizes performance by enabling users to group together multiple records into a single call, which reduces the overhead associated with starting and maintaining individual transactions for each record. This capability also minimizes the number of API calls required, which can be crucial when dealing with Salesforce API limits.

In addition, the Bulk API provides features like improved error handling and speed, which are essential for backup operations where the focus is on efficiently transferring vast amounts of data to ensure data integrity and availability without straining system resources.

The other APIs, such as REST, SOAP, and Streaming, while useful for various use cases, are not designed to handle large data volumes as efficiently as the Bulk API. The REST and SOAP APIs support a more synchronous, real-time approach to data interaction, making them less optimal for extensive data extraction tasks. The Streaming API focuses on event-driven scenarios rather than bulk data transfer, further confirming why the