Question:

> Hi, -----!
>
> I passed Oracle8 Performance Tuning exam recently, and I want to
> share some impressions about it. Here is an example question:
>
> What are two reasons you should keep rollback segments in
> tablespaces dedicated especially to rollback segments?
>
> A. You cannot take a tablespace offline unless it contains an
>      active rollback segment.
>
> B. Rollback segments may fragment
>
> C. High DML activity results in heavy I/O
>
> D. A single transaction can only use a single rollback segment
>
> [select two choices]
>
> I hope that I reproduced this exam question right. I understand
> that this question is Sylvan Prometric's intellectual property, but
> I just want to make this piece a bit better, if possible.
>
> What bothers me here is not the correct answer combination. You
> see, I'm not a native English speaker, so I just felt about this
> question
> that it was a LANGUAGE TRAP. I answered all the other answers
> quickly enough just to sit over the choice A for about 30 minutes,
> trying to figure out its exact neaning.
>
> So, can I hear from English-speaking DBAs what is the answer to
> this question?
>
> TIA and have fun.
>
> Alex.
>
>

Answer 1:

The statement in A is simply false. You can take tablespaces offline whether
or not they contain rollback segments. You cannot take a tablespace offline
when it contains an active rollback segment.
B is true
C is also true, better not have ALL activity in one tablespace
D is a fact of live and doesn't tell anything about the tablespace issue.

So far I never attended an exam I did a few trial exams, and my idea about
those is you need to reread many questions several times, to understand what
they mean. I'm sure the same is going to occur if they translate everything
into Dutch.

Hth,

Sybrand Bakker, Oracle DBA
 

Answer 2:

> A. You cannot take a tablespace offline unless it contains an
>      active rollback segment.

Not true so you can eliminate this one.
 
> B. Rollback segments may fragment

True.
 
> C. High DML activity results in heavy I/O

True.
 
> D. A single transaction can only use a single rollback segment

While this is true, is this a reason to put the RBS in a seperate
tablespace? No, so this is not one of the answers.

The Exam Guides (Couchman & Ault) make a big deal out of B & C. I
believe that this is the answer that the test was looking for. At least
that's what I answered when I took the test.

HTH,
Brian