Hi, Tom:
>Whichever one manages to get to the index page first will go through.
>The second one will block waiting to see if the first one commits,
>and will error out if so --- or proceed, if it aborts.
I see, this makes sense. What if the two transactions insert rows
that don't violate the constraint: will they be able to proceed in
parallel? Or will one wait for the other, because they both need to
update the shared index? I.e., does the mechanism work by waiting for
one index update to commit before permitting the next?
--Cliff