To prevent data inconsistencies, a transaction acquires a lock on the data before updating it. When another transaction is updating data and holding a lock on it, it waits for the lock to be released. A deadlock occurs when multiple transactions are waiting for data locked by another transaction, and neither can proceed.

PostgreSQL automatically detects deadlocks and resolves them by terminating one of the transactions.

deadlock_timeout specifies the wait time before initiating deadlock detection when a transaction is blocked waiting for a lock. The default value is 1s (1 second).

This doesn't necessarily mean a deadlock has occurred; the detection process only starts after the specified timeout.

A smaller value speeds up deadlock detection but increases the chance of unnecessary detection runs.

A larger value reduces unnecessary detection but increases the delay before a real deadlock is detected.

Since deadlock detection is itself a CPU-intensive process, it should be avoided as much as possible.

In environments with frequent deadlocks, reducing deadlock_timeout might seem like a quick fix, but the best approach is to prevent deadlocks in the application and increase deadlock_timeout to avoid unnecessary CPU-intensive detection.

Therefore, the correct answer is D.