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Re: High Water Mark ?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Sat, 27 Nov 1999 16:37:29 -0000
Message-ID: <943720755.20537.0.nnrp-01.9e984b29@news.demon.co.uk>

Hmm !

No wonder so many DBA's come up
with daft ideas these days - they've
taken the OCP exams.

  1. Minimising contention by moving data from one tablespace to another. I wonder what contention (realistically) could be affected by moving objects between tablespaces ?
  2. If you move an object from one tablespace to another then you have to create a new object - so the HWM is set to zero when you create the object - so no method will get data in 'below the hwm'.
  3. No doubt the exam is out of date, but where is the option for 'alter table move ?' Which could be done in 8.1, and is likely to be the 'best' option.
  4. No excuse for missing 'CREATE TABLE AS SELECT NOLOGGING' as an option. To do so suggests that all the other options might be a good idea. CTAS also allows for a parallel activity.
  5. Of course, since you have to recreate the object to get it into the second tablespace all the access rights disappear unless you take the export / import option: but dependencies get broken until you recompile everything in sight and that doesn't get fixed by import.
  6. Where's the bit that caters for the PK/FK constraints when you get to dropping the old copy of the data -
  7. Not to mention recreating the FK constraints to point to the new copy of the object afterwards.
  8. Of course, the question only asks about loading the data, not about how you would extract the data to have it ready for loading. So SQL*Loader conventional path is no more unreasonable than the rest of the answers
  9. Although direct load import does not exist, English grammar allows option (D) to mean use direct export, conventional import, so (D) is no more unreasonable than the rest of the answers.
  10. Option (E) (which I understand from other posters is the notional correct answer) is as defective as all the others - if you decide to export / import why aren't you doing a direct export and conventional import ?
  11. And its incomplete of course - how do you deal with an import that has to move an object from one tablespace to another anyway: import tends to put things back where they came from
  12. And if you do the export /import, would you do it with compress extents = y or n ?

In short -

    A bloody stupid question with a ridiculous choice     of answers that does nothing to check the real-life     skills of a potential DBA.

--

Jonathan Lewis
Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk

yewpc_at_rnd.celcom.com.my wrote in message <81l2jp$m0g$1_at_nnrp1.deja.com>...
>hi,
> I have a quenstion on one of the question in OCP8 Database
>Administartion (accessement test)
>"You need to minimize resource contention by moving some of the data in
>the HR_DATA tablespace to the HR_DATA2 tablespace. Which method would
>you use to load this data below the high water mark ?
>A. direct-load insert
>B. SQL*Loader direct path
>C. SQL*Loader conventional path
>D. Export and Import utilities using direct mode
>E. Exportand Import utilities using conventional mode
>
>The answer is E. but why ?
>Can anyone tell me how each of the above method change the high water
>mark ?
>Actually what is high water mark ? what is it purpose ? what dictionary
>i can use to query about it ?
Received on Sat Nov 27 1999 - 10:37:29 CST

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