Simon Riggs <simon@2ndQuadrant.com> writes:
> We need a function called transactionid_current() so a normal user can write
>        select virtualtransaction
>        from pg_locks
>        where transactionid = transactionid_current()
> and have it "just work".
That would solve that one specific use-case.  The reason I suggested
txid_from_xid is that it could also be used to compare XIDs seen in
tuples to members of a txid_snapshot, which is not possible now.
        regards, tom lane