How to speed up the query time after adding order by

Question

Hi,
In Form 6.0 front-end and 8i server, I put an "order by date
column desc" in Block Property and when I hit query button the
screen will bring up the most current date data instead of
oldest date data. The problem is slowing down the query time,
because the "order by" does the resorting work in the user temp
table space. The base table to be queried also contains two
varchar2(1500) columns and that also slow down the query time.
I am wondering if there is any other way to bring the current
records first without slow down the query speed ?
Any thought will be helpful and appreciated.
Thnaks!
Tony
null

Answer 1

anthony hsu (guest) wrote:
: Hi,
: In Form 6.0 front-end and 8i server, I put an "order by date
: column desc" in Block Property and when I hit query button the
: screen will bring up the most current date data instead of
: oldest date data. The problem is slowing down the query time,
: because the "order by" does the resorting work in the user
temp
: table space. The base table to be queried also contains two
: varchar2(1500) columns and that also slow down the query time.
: I am wondering if there is any other way to bring the current
: records first without slow down the query speed ?
: Any thought will be helpful and appreciated.
: Thnaks!
: Tony
What I have done is use hints to force the use of an index in
descending order. The part of the following example that
pertains to your question is the index_desc hint. Syntax and
suggestions for using hints are in the Oracle documentation.
The column you want to order desc by would have to be in an
index. The following example creates a view which you might not
need to do.
create or replace view v_sample_result as
select
/*+
first_rows
index ( sa )
index_desc ( t c_test_altk )
index ( r c_result_pk )
index ( lt )
null