If pessimistic detection is used here, is there a possibility that live lock occurs since transaction A and transaction B could keep on aborting when the other tries to write to node 3?

In relation to the question above, assuming that Transaction A occured earlier than transaction B, we can avoid this livelock situation by setting a rule that whichever transaction happened first can be the one to move forward, which would be A in this case, and B would be aborted

@mark indeed that pessimistic detection does not guarantee forward progress. See slide 47. @lee how would we know transaction A occurred earlier though? I though tie breaking cannot typically be time based.

I don't think breaking the tie between transactions based on time would be the best criteria since transactions could happen at the same time. An approach to make livelock less likely that involves time is to use some back-off scheme. This way, conflicting transactions are delayed for some time while the other can make progress.

There are a number of other ideas discussed for avoiding livelock on slide 47.