Rollback segments again

[Donna]

Hi,
I have read about rollback storage parameters in all kind of documentation
And I am not sure if MINEXTENTS should be 10,8,20 or x.
Could somebody explain why should be 10 or 20 and what is the impact if MINEXTENTS =2.

And if I don't ask to much
Is there a documentation that explain in depth how to interpret for example V$ROLLSTAT

Thank you!

[marist89]

It depends on your application. How big do your RBS need to be? What is your INITIAL and NEXT extent settings in the RBS tablespace? What is the relationship of your OPTIMAL RBS settings and your MINEXTENTS?

Personally, I like to have my minextents = the number of extents that will comprise my RBS when they are at their OPTIMAL size.

[Donna]

1.Big and small
2. INITIAL=NEXT for RBS tbs
3.OPTIMAL= INITIAL_EXTENT * INITIAL_EXTENT

[Donna]

Sorry!
I mean

1.Big and small
2. INITIAL=NEXT for RBS tbs
3.OPTIMAL= INITIAL_EXTENT * MIN_EXTENTS

[marist89]

If you already know what your OPTIMAL setting will be, just figure out the number of extents it will take.

PS. IMHO, there should be no such thing as "big" rbs and "small" rbs. All your RBS should be sized properly as to avoid ORA-1555 error messages.

[Donna]

1.Big and small transactions

Thank you

[pando]

a large minextents is to avoid dynamic extensions and blocking sessions