Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: undo header congestion? (8.0.5)

Re: undo header congestion? (8.0.5)

From: Sybrand Bakker <gooiditweg_at_sybrandb.demon.nl>
Date: Tue, 20 Jan 2004 22:45:36 +0100
Message-ID: <f48r00di9otd51f22t30ujgm9tl7gleo0s@4ax.com>


On Tue, 20 Jan 2004 19:33:18 GMT, Bjørn Augestad <boa_at_metasystems.no.spam.to.me> wrote:

>Sybrand Bakker wrote:
>
>> On Tue, 20 Jan 2004 15:47:40 +0100, Bjorn Augestad
>> <Bjorn.Augestad_at_bokklubbene.no> wrote:
>>
>>
>>>Some additional info: instance 1 has two rollback segments, and instance
>>>2 has just one (+ system).
>>
>>
>>
>> The number of rollback segments should be set according to the rule of
>> four: per 4 users 1 rollback segments, with a minimum of 4 rollback
>> segments, and rounded up.
>> Consequently both instances have too few rollback segments, which is
>> confirmed by the number of waits on the undo header block.
>>
>
>Thank you for answering. :-)
>
>Would you(or anyone else) consider it a serious case of misconfiguration
>to set up an instance with just one/two rollback segments, assuming
>25-50 users?
>
>Regards,
>Bjørn

One (excluding the system rollback segment) would be serious misconfiguration. Two would be debatable depending on the number of concurrent transactions. My guideline is using always 4 minimum, whatever small number of users there is. So if I would have to take over administration for this database, I would have adjusted the number of rollback segments.

Regards

--
Sybrand Bakker, Senior Oracle DBA
Received on Tue Jan 20 2004 - 15:45:36 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US