EXPLAIN PLAN

From: <inferno2000_at_my-deja.com>
Date: 2000/05/09
Message-ID: <8f84s0$gb$1@nnrp1.deja.com>#1/1

Let's start off some discussion on EXPLAIN PLAN and Hints in Oracle RDBMS. Does anyone know what /*+ ORDERED_PREDICATES */ do in Oracle 8i? Is it possible to rearrange order of predicates in the WHERE clauses so that Oracle perform short-circuit logic checking and skip those unnecessary clauses based on current row data?

For example:
SELECT
a.*
FROM table1 a, table2 b
WHERE a.f1 = b.f1 -- condition#1
AND a.f2 * 31 < b.f2 -- condition#2
AND EXISTS (select * FROM table3 c WHERE c.f1 = b.f3) -- condition#3

Is there a way to instruct the optimizer so that it will skip condition#3 if condition#2 is false?

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Before you buy. Received on Tue May 09 2000 - 00:00:00 CDT