I am studying on distributed transactions, mainly on the correctness criteria (e.g., serializability (SR) and snapshot isolation (SI) in replicated settings) and their implementations.

To avoid unnecessary efforts, I would like to know that

What are the known (or conjectural) impossibility results and lower bounds on the complexity of implementing distributed transactions conforming to some correctness criterion and/or some progress condition?

For example,

Is it possible to implement SI in a wait-free/lock-free manner in replicated settings?