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Re: Can outlines be fully reverse engineered?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Fri, 22 Oct 2004 07:36:56 +0100
Message-ID: <000901c4b801$86d32880$6702a8c0@Primary>

Not 100% possible - (at least until 10g, where the new variant on the leading()
hint may help).

If you look at outln.ol$hints, you will see it has columns

    table_tin
    table_pos

For some queries (particularly ones with suqueries, which yours may be given the
outline reference to sys_alias_1), Oracle has a mechanism which effectively dictates the order of table visit that you cannot emulate in 8i or 9i.

10g has the leading(t1, t2, t3 ....) hint, though, which may solve that problem.

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/seminar.html Optimising Oracle Seminar - schedule updated Sept 19th

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Received on Fri Oct 22 2004 - 01:32:30 CDT

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