Pando,


Point(according to original poster) is what would it take to run the query faster if you are having
multi million rows tables.

Having indexes on the columns of the where clause would apply the predicate first and it will reduce the resultset, however, its going to make query run much slower than not having indexes on it. 15% for a multi million rows table is quite a big result set.

Not having indexes on the columns in the where clause would have CBO do Full table scan and join the tables first and then apply filter(see the explain plan).


Indexes are preferred when selecting a very very small number of rows may be upto 5%.

Moreover, must try query both ways to and compare the timing.



Thanks,