RE: OCP Architecture question

With respect to evaluating answer number one, it's a bad question, because you have know way to know whether the context is supposed to be  

1. assume a fixed rollback segment size, but use fewer, larger extents; or
2. make the rollback segment larger by using the same number of larger extents.

In context (a), #1 is a bad answer. In context (b), it's a better answer, but it's still poor.  

The thing that really chaps me about stupid certification questions like this is that no answer among the choices listed is really the right thing for you to try to do, which is:  

<shout>FIX THE QUERY THAT'S TAKING SO LONG TO RUN.</shout>  

In other words, make queries run quickly enough that they don't require multiple-hour-old undo blocks to produce read-consistent results.  

Jacking around with rollback segments is just a kludge that will produce results far inferior to what you can achieve by attacking the query problem at its root.  

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com

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-----Original Message-----
Tim Gorman
Sent: Thursday, August 14, 2003 10:54 PM To: Multiple recipients of list ORACLE-L  

They all allow the RBS to be bigger. More space available for RBS roughly equals fewer ORA-01555, for most situations...

on 8/14/03 6:24 PM, Ryan at rgaffuri_at_cox.net wrote:

Im using the self test software and here is a question... I dont like the answers. Please tell me if Im wrong.

Which Three methods can be used to avoid snapshot too old errors. This is for the 8i test.

1. User larger extents
2. Increase MAXEXTENTS for existing rollback segments
3. Create rollback segments with higher optimal values
4. Create rollback segments iwth high minextents
5. Run long queries when transaction processing is high.

Ruling out 5 is obvious. The test says its.

1,3,4

How does using large extents help this? What about a higher minextents value?  

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Author: Cary Millsap
  INET: cary.millsap_at_hotsos.com

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