Re: optimizer_mode = choose ??

From: SANJAY PURI <skp_at_ix.netcom.com>
Date: 3 Oct 1994 16:37:33 GMT
Message-ID: <36pc0d$cd_at_ixnews1.ix.netcom.com>


In <k1JJTc4w165w_at_vllyoak.resun.com> jp_at_vllyoak.resun.com (Jeff Perry) writes:

>
>The V7 Oracle Admin manual indicates two possible settings for the
>OPTIMIZER_MODE parameter: RULE & COST. Our databases don't have
>this parameter specifically set, and a query of the v$sysstat view
>indicates optimizer_mode = CHOOSE. What kind of optimization takes
>place with such a setting? It *appears* to default to COST if any
>statistics are available. This is relative to version 7.0.13.1.
>--
>Jeff Perry
>jp_at_vllyoak.resun.com
>

If the optimizer mode is not set to RULE, ORACLE7 will assume COST as the Base. In any case, if you want to user RULE as the base for some of the queries, you can do so by modifying the appropriate query to give hint to the Optimizer.

Vijay Kumar Nair Received on Mon Oct 03 1994 - 17:37:33 CET

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