Using GRAPH.COPY in conjunction with MULTI/EXEC is unreliable

[JoonasC]

This is related to PR FalkorDB/JFalkorDB#27, it seems that using GRAPH.COPY in conjunction with MULTI/EXEC is not reliable (Sometimes the graph gets copied properly and other times it doesn't). This causes a unit test in the aforementioned PR to sometimes fail and sometimes work.

[swilly22]

Thank you @JoonasC for brining this to our attention, MULTI/EXEC doesn't play nicely with Falkor's consistency model and shouldn't be used with GRAPH commands, we'll consider removing MULTI/EXEC from Falkor's exposed Redis commands.

[JoonasC]

@swilly22 It would be problematic for me if MULTI/EXEC was removed, because I need to have some way to perform checks on a graph before I mutate it as I explained here: #502 (comment). Do you have an idea how I can do that without using MULTI/EXEC? One alternative would be pessimistic locking, but I would like to avoid it because it is more expensive than optimistic locking.