You have the estimated processing time viewable in the explain tab of the running query, as far as
'going to finish' , no.
If the query has run before and DBQL logging is enabled for the user then you can view historical runs in dbqlogtbl for the same to have an idea. The load on the system also needs to be considered.
Sure, I agree.
the explain plan is your best indication of query efficiency. The estimated processing time (cost)for a particular step will give you an indication of how expensive a step may be and without historical runs of the query, is your only tool to estimate how long the query may actually run.(providing statistics are current)