Barry,
The term "private" or "public" is relevant to an instance not to
a transaction and is "configuration independent". Which means
that I can create both public and private rollback segments in
both OPS and non-OPS configurations. The term "private" is
definitely not an OPS-only term. When rollback segments are
created by default without any keywords, they are created as
"private" rollback segments. Even in a non-OPS environment
"normal" rollback segments created, are "private". The key
characteristic of a "private" rollback segment is that, if you
don't put in in the init.ora, it will not automatically come
online.
It is only when "public" rollback segments are required, that
the keyword - PUBLIC is used. The use of public rollback
segments was originally devised many years ago for OPS
configurations with many many instances (e.g. the n-Cube
platform could theoritically support 512 nodes, hence
theoritically 512 instances). Instead of having to configure a
rollback segment init.ora parameter for each of the 512
instances, the idea was to use public rollback segments, so that
each instance could bring online, a set of rollback segments
from the "public pool", purely based on the ratio of :
(transactions/transactions_per_rollback_segment)
But for most "normal" OPS configurations, the number of
instances are not that much (2-8 maybe), so using private
rollback segments (default) and configuring the rollback_segment
parameter for each of the init.oras was not a big deal. In fact
using private rollback segments facilitates better management
and localization of these objects.
Hope that helps,
Gaja.
- barry botuck <botes_at_hq.idt.net> wrote:
> Gaja:
> Are you discussing ops?
> .. I thought that the term private rollback segment is an
> oracle parallel
> server concept ONLY,
>
> Barry
>
> -----Original Message-----
> From: root_at_fatcity.com [mailto:root_at_fatcity.com] On Behalf Of
> Gaja Krishna
> Vaidyanatha
> Sent: Tuesday, July 11, 2000 1:26 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Rollback segments offline on database restart
>
> Mariana,
>
> One should probably always choose option #1 , as #2 is
> dependent
> on the ratio :
> (transactions/transactions_per_rollback_segment).
> What this means, is that if the value of transations=100 and
> transactions_per_rollback_segment=4, then the total number of
> rollback segments (public and private) that Oracle will bring
> online on startup, will not exceed 25.
>
> So, rather than going and fiddling with those 2 parameters to
> make things work, it should be preferred to just create all
> rollback segments as "private" and put their names in the list
> of values in the rollback_segments parameter. It must also be
> noted here that the number of "actual transactions per
> rollback
> segment" has nothing to do with the
> transactions_per_rollback_segment parameter. The number of
> actual transactions per rollback segment is O-S and
> db_block_size dependent.
>
> Best Regards,
>
> Gaja.
>
> --- "Galleri, Mariana" <MGalleri_at_uniFON.com.ar> wrote:
> >
> > Ravi,
> >
> > You have two options.
> >
> > 1- You have to use rollback_segments parameter and list out
> > all(more than
> > 25) segments
> > there, or
> > 2- You can create public rollback segments and you don't
> need
> > to use
> > rollback_segments parameter
> >
> > Regards.
> >
> >
> > -----Mensaje original-----
> > De: Ravi Babu [mailto:lravibabu_at_hotmail.com]
> > Enviado el: Martes 11 de Julio de 2000 10:45
> > Para: Multiple recipients of list ORACLE-L
> > Asunto: Rollback segments offline on database restart
> >
> >
> > Hello,
> > I have created 25 rollback segments. Now whenever i restart
> > the database few
> >
> > rollback segments are offline. To one procedure i have
> > assigened one
> > rollback segment with the help of 'set transaction use
> ....'.
> > Now whenever
> > the database is restarted around 5-7 rollback segments are
> > offline, which i
> > manually have to set it online again. How to get this thing
> > done. Do i have
> > to use rollback_segments parameter and list out all(more
> than
> > 25) segments
> > there?
> > Please help.
> > Ravi.
> >
> >
>
> > Get Your Private, Free E-mail from MSN Hotmail at
> > http://www.hotmail.com
> >
> > --
> > Author: Ravi Babu
> > INET: lravibabu_at_hotmail.com
> >
> > Fat City Network Services -- (858) 538-5051 FAX: (858)
> > 538-5051
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> > Author: Galleri, Mariana
> > INET: MGalleri_at_uniFON.com.ar
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>
> =====
> Gaja Krishna Vaidyanatha
> Director, I-O Management Products
> Quest Software Inc.
> (972)-304-1170
> gajav_at_yahoo.com
>
> "Opinions and views expressed are my own and not of Quest"
>
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> --
> Author: Gaja Krishna Vaidyanatha
> INET: gajav_at_yahoo.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858)
> 538-5051
> San Diego, California -- Public Internet access /
> Mailing Lists
>
> To REMOVE yourself from this mailing list, send an E-Mail
> message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru')
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> also send the HELP command for other information (like
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>
> --
> Author: barry botuck
> INET: botes_at_hq.idt.net
>
> Fat City Network Services -- (858) 538-5051 FAX: (858)
> 538-5051
> San Diego, California -- Public Internet access /
> Mailing Lists
>
> To REMOVE yourself from this mailing list, send an E-Mail
> message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru')
> and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from).
> You may
> also send the HELP command for other information (like
subscribing).
Gaja Krishna Vaidyanatha
Director, I-O Management Products
Quest Software Inc.
(972)-304-1170
Received on Wed Jul 12 2000 - 12:22:04 CDT
