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RE: OCP Question (Perf Tuning)

From: Niall Litchfield <niall.litchfield_at_dial.pipex.com>
Date: Tue, 06 Jan 2004 13:54:26 -0800
Message-ID: <F001.005DBE0A.20040106135426@fatcity.com>


Jonathan noted that
> > Nope. The answer is b). In the FIRST_ROWS mode, optimizer
> prefers NL
> > to
> all other
> > methos despite the price.
> >
>
> Unless the alternative is a full tablescan on the inner
> table - in which case merge or hash joins can be
> considered.

For some reason hash joins were excluded from the question. I can't speculate as to what, other than oversight or limiting the answers to 4, the reason for this might be.

I suspect the answer *wanted* is b) the focus being that FIRST_ROWS favours index scans and NL joins. ISTM that d) ought to be ruled out as it refers to rows not blocks but as usual I am probably wrong.

Niall

OCP DBA (the last time you'll see that sig for a while....).

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Author: Niall Litchfield
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Received on Tue Jan 06 2004 - 15:54:26 CST

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