index usage question

From: usmrall <srallapally_at_netscape.net>
Date: Tue, 30 Nov 1999 18:57:37 GMT
Message-ID: <8216mu$rqa$1@nnrp1.deja.com>

Hello all,
How does Oracle decide which index to use, in a rule based world ? I did read up on the tuning guid for RBO, but I have a wierd case so here goes...
my where clause is as follows
where client = 50 and document_num = 100 and rownum < 2 there are two indexes
index a: client,company_code,posting_date,document_num (PK index) index b: client,company_code,posting_docu,document_num

Oracle ends up using the primary key index. Now, I was under the impression that in RBO an index matching the WHERE predicate would be used ! Was I wrong or is there some logic to this?

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Before you buy. Received on Tue Nov 30 1999 - 12:57:37 CST