Query execution time remaining

I want to clear my confusion about how to find the execution time remaining for a SQL query which is still running.

My understandings are as below. Please correct me if my understanding is wrong.

P.S - In the current client place where I am working, due to license issues I can not use AWR / ADDM.

Oracle - 10.2.04
OS - SUN & HP

S1 - If the query is executing longtime, showed up in v$session_longops then it will populate the TIME_REMAINING column for that particular operation like table scan, index scan, hash join, or sort etc but not for the whole query.

S2 - If the query is executing longtime, but not showed up in v$session_longops because of the criteria is not satisfied then we can check the query in v$sqlarea and find ELAPSED_TIME but I didn't find any thing to find how much time remaining.

Looking for your suggestions to find the actual REMAINING TIME for a given query which is currently running in the database.

Thanks,

how on earth is the database going to know who long a whole query has left to run

cannot predict the future

Thanks Davey.

I expected like, when oracle is able to predict the TIME_REMAINING for the executions in v$session_longops then it should have some predictions about the whole query based the stats available and the execution plan it generated.

Thanks,