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Re: How "deterministic" are EXPLAIN PLAN results?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 10 Apr 2003 12:46:18 +0100
Message-ID: <b73lh9$qvs$1$8300dec7@news.demon.co.uk>

His information is a little out of date, anyway.

There is a hidden parameter that controls whether the session level optimizer mode is pushed into PL/SQL or not.

Somewhere around 8.1.6/7 its default value was changed from false to true

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"Vladimir M. Zakharychev" <bob_at_dpsp-yes.com> wrote in message
news:b73k6u$462$1_at_babylon.agtel.net...

>
> Actually, what Sybrand probably meant is that the OPTIMIZER_MODE
> setting is ignored in PL/SQL and is always assumed ALL_ROWS.
> But to my knowledge hints are not ignored, so if you hint your
> query with /*+ FIRST_ROWS */, it will be executed in this mode
> by both PL/SQL and SQL engines. By the way, this may not apply
> to 9i since PL/SQL and SQL use the same engine in 9i.
>
Received on Thu Apr 10 2003 - 06:46:18 CDT

Original text of this message

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