UNNecessary indexes ??

From: <sat0789_at_fastmail.fm>
Date: Thu, 15 May 2003 10:51:55 -0800
Message-ID: <F001.0059A00D.20030515105155@fatcity.com>

Hello All,
 We have a table for (eg) say
table x with 4 number cols (x1,x2,x3,x4)..

There is a pk constraint on x1 an a unique key constraint on x2,x3 Now we also have non-unique indexes on
index x2_idx on col x2
index x2_x4_idx on col x2,x4

I would presume that index x2_idx alone is not needed as the unique index or index x2_x4_idx will satisfy
queries with col x2..

My question is can i also eliminate index x2_x4_idx ?? If i have query with the where clause x2 = 333 and x4 = 444 then would using index x2_x4_idx be good or
using unique index be a good choice , since CBO does a index range scan while using both the indexes...
I am trying to eliminate unnecessary indexes created by developers ....

Thanks,

Sathish

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