Hi,

i have a question about two parallel transactions which insert the
same key.

Assume that key A does not yet exist.

T1 Begin
T2 Begin
T1 Insert A
T2 Insert A
T1 Commit
T2 Commit

My guess is: "T2 Insert A" is a conflict with the previous insert of
T1. But i also think that in a MVCC database the conflict can only be
resolved when T2 is committed. What happens then? Does the commit
fail, or is A silently overwritten? Or is the typical behaviour in
this case implementation-specific?

Thanks for your answers,
Christoph