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Why my index is not used?

Bruce Jin
Ranch Hand

Joined: Sep 20, 2001
Posts: 671
These 2 queries take 23 seconds on Oracle:

(1) select invline from mrcmpower.bisales order by invline desc
(2) select invline from mrcmpower.bisales where invline >0 order by invline desc

They should be the same because all 2 million rows in the table have invline > 0.

Then I added index: create index mrcmpower.index2 on mrcmpower.bisales (invline desc)

Now query (1) still takes 23 seconds and query (2) only takes 0.01 second.

Why query (1) does not use the index?


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Carol Enderlin
Ranch Hand

Joined: Oct 10, 2000
Posts: 1364
they should?
I agree. Here's the link:
subject: Why my index is not used?
It's not a secret anymore!