Which processes are considered single-threaded and will improve performance with additional instances?

The correct response highlights the Backgrounder process as being single-threaded and benefiting from having additional instances. Backgrounders are responsible for handling tasks that run in the background, such as generating extract files, running subscription emails, and executing scheduled tasks. When multiple instances of Backgrounders are deployed, they can run these processes concurrently, allowing for more tasks to be managed simultaneously. This parallelism effectively enhances performance, especially in environments with high demand for background processing.

In contrast, other processes listed may serve different functions. For instance, the Cache Server is designed to improve query performance by caching data, while the Gateway processes requests and serves Web traffic. These processes do not necessarily operate in a single-threaded manner or benefit in the same way from adding more instances. Elastic Server focuses on dynamic resource allocation based on demand but also does not fall into the single-threaded category. Understanding the distinctions between these processes and their threading models aids in optimizing Tableau server performance effectively.