The Discrete collision detection mode uses a discrete collision detection algorithm, which checks for collisions on each physics timestep.
Discrete is the default collision detection mode, and by far the least computationally demanding. However, it can miss collisions that occur between physics steps, so it’s usually not suitable for fast-moving collisions.
If your collisions happen too quickly for discrete collision to pick them up, you can try one or both of the following solutions:
Experiment with both and profile the results to find the right solution for your project.