Absolutely identical plans, and traces -
the only change was that the cost of the
sort step went up. This was testing on a
very simple plan too, trying to trade between
sort (order by)
and an index driven order by - so nothing as
complex as messing with a merge join.
If you're interested in the specific example, I'll post
you the script offline to recreate the test case: I'll have
to pull it from a different machine, though, which is why
I can't post it right now.
BTW - I still believe quite firmly that hints are
never ignored. They may be syntactically incorrect,
there may be bugs, they may never become relevant;
but I don't think they are ignored. However, I will agree
that there are more and more grey areas in 9.2 where
the increased scope for (internal) query rewrites is so
extensive that it is becoming a lot harder to decide why
a hint appears to have been ignored.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Coming soon one-day tutorials:
Cost Based Optimisation
Trouble-shooting and Tuning
Indexing Strategies
(see http://www.jlcomp.demon.co.uk/tutorial.html )
____UK_______March 19th
____USA_(FL)_May 2nd
Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )
____USA_(CA, TX)_August
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
-----Original Message-----
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Date: 16 February 2003 23:07
hint
>Did the increase in SORT_AREA_SIZE change the execution plan,
regardless of
>the use of hints (since certain hints can easily be ignored)? Larger
>SORT_AREA_SIZE might encourage the CBO to choose a SORT-MERGE join,
for
>example...
>
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Author: Jonathan Lewis
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