Re: pg_basebackup and replication slots

Now, do we plan to do something about the creation of a slot. I
imagine that it would be useful if we could have --create-slot to
create a slot when beginning a base backup and if-not-exists to
control the error flow. There is already CreateReplicationSlot for
this purpose in streamutils.c so most of the work is already done.
Also, when a base backup fails for a reason or another, we should try
to drop the slot in disconnect_and_exit() if it has been created by
pg_basebackup. if if-not-exists is true and the slot already existed
when beginning, we had better not dropping it perhaps...