Order by taking too much time. Tried using all_rows hints no use.Pls advice

Question

I run the query without order by and finishes in less than 30 sec. Once you have order by,query just hangs. Pls advice. Thanks.
select col4,col6
from
table a , table b, table c
where a.col1 = b.col2
and a.col1 = c.col3
order by col1,col2 desc

Answer 1

If you put the \ tag (6 characters, all lower case) around the text where you want to preserve the formatting, the query plans you post are going to be much more readable.
The optimizer's estimates appear to be correct and the plan is the same other than the ORDER BY.  I would, therefore, be highly inclined to believe as I was discussing earlier that the "30 seconds" figure that you're discussing is the time to fetch the first few rows, not the time to fetch the last row.
Can you define "hang"?  How long do you let the query run before killing it?  Minutes?  Hours?  Days?
What are the wait events associated with the query when it is running?  If the optimizer is correct that you're generating 5.4 million rows and a little over a GB of data that needs to be sorted, that should be expensive but that shouldn't take hours.
What is the business problem you're trying to solve?  Sorting implies that you are trying to return results from a report to a user.  But, obviously, no user is ever going to page through 5.4 million rows of results.
Justin