How best can i optimise this script

Question

I have a script the loops through a table and function. it works fine but it takes a longer time complete even though resources are given. the code below is just the same code i used how best can i represent it for speed even though i have all resources.
For each_member in ( select from MemberTable where MemberID = 'ALL')*
Loop
Begin
if Age >= 18 then
hold:= 'Adult'
end if;
For Each_history in (select Acct,fx_function(each_member.ID,each_member.Acct) BR,
Movement from History a where history_ID =each_member.Id)
loop
Begin
insert into NewFilteredData (act,BR,mvt)
values (Each_history.Acct,Each_history.BR,Each_history.Movement);
end loop;
end loop;
end loop;
commit;
How best can i optimize this script to move data faster because they are a lot about 6000000 records to be moved.
please help.
Edited by: kama021 on Aug 25, 2009 12:48 PM
Edited by: kama021 on Aug 25, 2009 12:48 PM

Answer 1

Unless something is horribly wrong (i.e. the optimizer picks a radically incorrect plan), if you can do something in SQL, it will always be faster to do it in SQL. Doing things in PL/SQL, particularly using cursor FOR loops and single row inserts, is the slowest possible way to do anything (well, other than having nested FOR loops).
Long before you start looking at things like the APPEND hint, I would focus on implementing a single SQL statement that generates the correct results. Once you have that and you have a benchmark, you can decide whether it is "fast enough". If it is (and I suspect it will be), you don't have to delve any deeper. If you need more performance, you can start looking into parallelism, the APPEND hint, etc. but be aware that this generally increases the complexity of the system.
Justin