RE: hinting and the rule based optimizer

From: Goulet, Dick <DGoulet_at_vicr.com>
Date: Thu, 1 Apr 2004 15:54:16 -0500
Message-ID: <4001DEAF7DF9BD498B58B45051FBEA656D8356@25exch1.vicorpower.vicr.com>

Best hint of all, DON'T.

Dick Goulet
Senior Oracle DBA
Oracle Certified 8i DBA

-----Original Message-----

From: ryan.gaffuri_at_cox.net [mailto:ryan.gaffuri_at_cox.net] Sent: Thursday, April 01, 2004 3:04 PM
To: oracle-l_at_freelists.org
Subject: hinting and the rule based optimizer

We have a legacy 8.1.7.3 instance that is in RBO mode. My group does not = own it, so we cannot change it to CBO.

When I hint anything from an index to ordered, etc... it switches to the = CBO and since nothing is analyzed, it's an even worse plan... Not = allowed to analyze the tables either because it's not our property.

Any rules around hinting the RBO in 8.1.7.3? Why would it switch to the = CBO from a simple hint? I never use the RBO so please bare with me.=20

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Received on Thu Apr 01 2004 - 15:16:13 CST