create rollback segment on LMT use UNIFORM SIZE is ok?

[xiongye]

Hi: I do not know in 8.1.7 create rollback segment on local managed tablespace use UNIFORM SIZE is properly? Thanks !!!

[marist89]

RBS is an ideal candidate for LMTs. First, create your RBS tablespace:
CREATE TABLESPACE rbs1
DATAFILE '/u01/oradata/mysid/rbs101.dbf'
SIZE 10M
AUTOEXTEND ON NEXT 10M MAXSIZE 2000M
EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M;

Then, create your RBS with the appropriate minextents parameter:
CREATE PUBLIC ROLLBACK SEGMENT rbs101
TABLESPACE rbs1
STORAGE (minextents 8 optimal 8M):
ALTER ROLLBACK SEGMENT rbs1 ONLINE;

[ronnie]

Hi,

I already have my RBS as dictionary managed and the database is live production.

How do I go about making / converting it to LMT and whats the ideal configuration for a LMT for rollbacks.

what kind of performance gains will one see if I convert it to a LMT.


Thanks

[marist89]

The best way to convert to a LMT on a live database is create new RBS, place them online, take your existing RBS offline, and drop your existing RBS.

The ideal configuration is dependant on your database usage. If you have 8M RBS now, you will probably want to keep 8M RBS.

You will see a slight performance gain if your RBS are constantly growing and shrinking. If your RBS are sized properly, you might not see any performance increase.

[ronnie]

Originally posted by marist89

You will see a slight performance gain if your RBS are constantly growing and shrinking. If your RBS are sized properly, you might not see any performance increase.

What other incentive do I have to convert my RBS to LMT.

Thanks

[marist89]

People will admire you and think you're cool?

[ronnie]

Originally posted by marist89
People will admire you and think you're cool?

and why will they think that I am Cool and not a Fool , and that I should go back to school ......
:-)


Just trying to rhyme it up.

[ronnie]

Any suggestions........

[marist89]

jump in the pool you tool