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From: mao@eden.Berkeley.EDU (Mike Olson)
Newsgroups: comp.databases,comp.unix.questions
Subject: Re: Oracle - what sort of database system is it?  Is it for Unix?
Message-ID: <10607@pasteur.Berkeley.EDU>
Date: 30 Jan 91 17:44:41 GMT
References: <1991Jan29.152745.9028@cs.odu.edu> <1991Jan30.161141.24870@inel.gov>
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Reply-To: mao@postgres.Berkeley.EDU (Mike Olson)
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In article <1991Jan29.152745.9028@cs.odu.edu> aiko@cs.odu.edu (John K Hayes)
asks regarding oracle:

> Does it run on VAX VMS?  
> Can someone describe generally what Oracle is?

i know that early versions of oracle did not include a query optimizer.
qualifications were evaluated left-to-right in the user's query.  this
led to some predictable problems:  the user was not insulated from changes
in data representation, and had to expend a fair amount of energy in
optimizing queries by hand by ordering qual clauses cleverly.

do later releases of oracle include a query optimizer?  at what release
level was one added?  and what (roughly) is the cost function used to
pick a plan?  the last question is intended to discover whether oracle's
query optimizer is less than, equal to, or greater than the standard
optimizer that was designed for system r in the 1970's.

any oracle implementors out there?
					mike olson
					postgres research group
					uc berkeley
					mao@postgres.berkeley.edu