Optimistic vs. Pessimistic locking

Question

I understand the differences between optimistic and pessimistic locking. Now could someone explain to me when I would use either one in general?

And does the answer

Answer 1

In addition to what's been said already:

• It should be said that optimistic locking tends to improve concurrency at the expense of predictability.
• Pessimistic locking tends to reduce concurrency, but is more predictable. You pay your money, etc ...