Oracle-L: RE: Do you ever have days where you dont want to think ?

From: Kirsh, Gary <gary.kirsh_at_gs.com>
Date: Fri, 17 May 2002 14:03:24 -0800
Message-ID: <F001.00463C5A.20020517140324@fatcity.com>

It's not using the index because of the NOT IN - it doesn't help to search an index to see what's NOT in it. Did you try rewriting it to use a NOT EXISTS instead?
Gary

Gary Kirsh
Next Extent Consulting

-----Original Message-----
Sent: Friday, May 17, 2002 5:23 PM
To: Multiple recipients of list ORACLE-L

I just just wanna go lie on a beach naked on some remote island far far away and not think of anything for a month.

Here is the issue.....

I have a query that looks like this ...

select a.f1, a.f2, a.f3, a.f4 from table1 a where a.f1 not in
( select b.n1 from b );

there is a primary key index on b.n1
there is a concatenated primary key index on a.f1,a.f2,a.f3 there is a non-unique index on a.f1

the query shows that the index is being used on table b, but no indexes are being used on table a.

Mike
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Author: Johnson, Michael
INET: Michael.Johnson_at_oln-afmc.af.mil

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Author: Kirsh, Gary
INET: gary.kirsh_at_gs.com

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