HOW TO - Insert large number of rows fast

Question

I have a tables A , B and C and I select some data from A, B and C using some complex criteria.
Table A B and C has 10mil rows.
final rows to be insert into table D is about 3mil.
Currently the rows are inserted one at a time and there are 3 mil inserts in the plsql.
What is the best way to create these rows.
psudocode
begin
for loop ..... loop
--compled selection criteria.
insert into D ..... ;
end loop ;
end ;
SS

Answer 1

is there a way to optimize the inserts.The inserts takes very little time
Re: Insert Statement Performance Degradation
In this example the same number of inserts into the same table takes 0.03 seconds to insert 100,000 rows, and 3.06 seconds when looped. If the entire insert operation was optimized away to take zero time, the loop would still take 3.03 seconds, which represents a performance increase of a little under 1%.
As I said it is not a single query by which I build a row for insert into table D, It is
a complex operation which is not necessary to explain here.This is the slow part that needs optimizing.