Oracle-L: RE: What's your opinion: ALL_ROWS vs. FIRST

From: John Kanagaraj <john.kanagaraj_at_hds.com>
Date: Mon, 04 Nov 2002 12:38:50 -0800
Message-ID: <F001.004FB5FF.20021104123850@fatcity.com>

Hi Mike,

> Your article was very good in describing RBO vs. CBO. I hope
> you don't mind
> me using it to help better describe why we're switching from
> RBO to CBO to
> my team.

I forgot to mention this before, but you should also look at Tim Gorman's excellent paper on the CBO at http://www.evdbt.com - search in the library.

> On the other hand it didn't help me much in practical use of ALL_ROWS
> (CHOOSE) vs. FIRST_ROWS. I understand this was out of the scope of the
> paper.

Yes, but we can always discuss this here in the list :) The problem I have with the FIRST_ROWS is that _all_ queries would default to use this mode. While this may be good for a specific interactive query, it certainly would perform poorly for batch jobs, more so when the table joins larger tables. IMHO, you are better off leaving it to default to CHOOSE and control specific modes. This can be done via a variety of methods, including login triggers, Outlines, anf finally the code itself.

> Note: When leaving your web page I was notified that my IP address was
> captured. I didn't like that.

My web page is served by Yahoo! Geocities, and I obtained that when it was free (and still is free). I suppose that they capture some info and do manipulate cookies. This is the first time, though that I have come across such a message. I will need to investigate further...

Hth,
John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002

What would you see if you were allowed to look back at your life at the end of your journey in this earth?

The opinions and statements above are entirely my own and not those of my employer or clients ** -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: John Kanagaraj INET: john.kanagaraj_at_hds.com

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RE: What's your opinion: ALL_ROWS vs. FIRST_ROWS