Which types of operations require switching from a multithreaded approach to an asynchronous one to improve efficiency: interacting with a database, data exchange between servers, or CPU processing?

The asynchronous approach increases efficiency in operations where there is I/O waiting, rather than active CPU loading.

• Database interaction — often requires waiting for a server response, so asynchrony allows not to block the thread and to handle other tasks.

• Data exchange between servers — also an I/O operation, where asynchrony helps to efficiently utilize resources.

• CPU-bound tasks — these are computational operations that require active CPU usage. Asynchrony does not help here; it is better to use multithreading or multiprocessing.

In summary, to improve efficiency, it is advisable to switch to an asynchronous approach for database operations and network exchanges, and to use parallelism for CPU-intensive tasks.