Temp Tablespace Unable to Extend

I had a complex query generated by a Microstrategy report. It kept falling over with a "unable to extend Temp Tablespace". I knew its to do with the group by statement as it ran ok without the group by.The Temp tablespace was 4 GB which I tend to think should be enough.

I searched a lot on the internet for solution of this problem. Tried all the clever things using the no_parallel hint, increasing the sort_area_size, the pga_aggregate_target, used the new 10g facility to suggest a new profile which changed the plan but all to no avail in solving the temp tablespace problem.

Finally I went back to the drawing board and re-examined the query generated by microstrategy. I then relaized that two of the tables in the join were not needed at all to get the columns and the aggregate we wanted and that was the solution to the problem.

Conclusion is who said with 10g there is no more need for DBA???