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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Monitoring occurence of snaphot too old
You are talking about a completely different thing which is overwriting
blocks were being used by a committed TX while I was talking about
preventing wraps from happening!
Not having optimal prevents wraps in the RBS.
What Jared suggested (having a TX in each RBS) will not also prevents also overwriting blocks used by a committed TX.
Waleed
-----Original Message-----
To: Multiple recipients of list ORACLE-L
Sent: 8/4/02 12:53 AM
Even not setting optimal (or leaving optimal at null) does not prevent
the
RBS blocks being overwritten if they represent a commited transaction.
Hemant
At 07:18 PM 03-08-02 -0800, you wrote:
>Why do you have to do this if you can easily unset the optimal settings
for
>the RBS (optimal=null)?
>
>
>Waleed
>
>-----Original Message-----
>Sent: Saturday, August 03, 2002 2:09 PM
>To: Multiple recipients of list ORACLE-L
>
>
>
>There is another solution for special cases.
>
>Start a transaction in each rollback seg and never commit it.
>This prevents wraps to the head of the RBS.
>
>I've had to do this with certain SAP operations that run for
>days at a time, and will generate ORA-1555 if this precaution
>is not taken. It's suitable for long running jobs where you
>have no influence with teh duhvelopers.
>
>Details can be found at Steve Adams site, www.ixora.com.au.
>
>Jared
>
>
>On Friday 02 August 2002 21:13, Mladen Gogala wrote:
> > Well, 1555 happens when the query is unable to construct a read
> > consistent version
> > because rollback segment blocks have been reused by other
transactions.
> > The only solution
> > is to
> > a) have sufficiently large rollback segments so that a transaction
can
> > get unused rollback segment space without reusing recently
> > allocated space.
> > b) NOT have very long running queries.
> >
> > Conceptually, in my opinion, the infamous "snapshot too old" comes
from
> > mixing
> > DW and OLTP functions in the same database. A good practice is to
have
> > a "reporting
> > database" as a separate instance and populate it in some way
> > (replication, SRDF,
> > standby, self written programs). The reporting database can then be
> > re-indexed with
> > bitmap indexes and used for reports only. Things like that are (now
> > this is for DW
> > purists) called ODS or opeational data stores and are populated
> > approximately once a
> > week. Only very small daily reports are run against the main OLTP
> > database.
> > If you separate your functions like that, ora-1555 will become a
> > distant memory.
> >
> > On 2002.08.02 19:23 Mohammed.Ahsanuddin_at_VerizonWireless.com wrote:
> > > Hi,
> > >
> > > Yes, it is 8i..I was more interested in catching snapshot too old
> > > before it
> > > happens..does not seem possible..
> > >
> > > But, my thanks to everyone who responded..
> > >
> > > Mohammed Ahsanuddin
> > > Oracle DBA
> > >
> > >
> > >
> > > -----Original Message-----
> > > Sent: Friday, August 02, 2002 2:19 PM
> > > To: Multiple recipients of list ORACLE-L
> > >
> > >
> > > Yes. I didn't see the version it the other guy's post.
> > > Was it 8i?
> > >
> > > > -----Original Message-----
> > > > From: Farnsworth, Dave [mailto:DFarnsworth_at_Ashleyfurniture.com]
> > > > Sent: Friday, August 02, 2002 1:54 PM
> > > > To: Multiple recipients of list ORACLE-L
> > > > Subject: RE: Monitoring occurence of snaphot too old
> > > >
> > > >
> > > > Isn't the UNDO_RETENTION parameter a new one for 9i and does
> > > > not exist in 8.x and lower.
> > > >
> > > > Thanks,
> > > >
> > > > Dave
> > > >
> > > > -----Original Message-----
> > > > Sent: Friday, August 02, 2002 12:05 PM
> > > > To: Multiple recipients of list ORACLE-L
> > > >
> > > >
> > > > Just set the UNDO_RETENTION parameter to 4 hours and forget
> > > > about the 'snapshot too old'. It's no longer happening.
> > > >
> > > > > -----Original Message-----
> > > > > From: Mohammed.Ahsanuddin_at_VerizonWireless.com
> > > > > [mailto:Mohammed.Ahsanuddin_at_VerizonWireless.com]
> > > > > Sent: Friday, August 02, 2002 12:14 PM
> > > > > To: Multiple recipients of list ORACLE-L
> > > > > Subject: Monitoring occurence of snaphot too old
> > > > >
> > > > >
> > > > > Dear List members,
> > > > >
> > > > > I was wondering if there is a way to monitor the database and
> > > > > tell if there
> > > > > is a possiblility of snapshot too old error occurence.
> > > > >
> > > > > Any input is highly appreciated..
> > > > >
> > > > > Thanks
> > > > >
> > > > > Mohammed Ahsanuddin
> > > > > Oracle DBA
> > > > >
> > > > > --
> > > > > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > > > > --
> > > > > Author:
> > > > > INET: Mohammed.Ahsanuddin_at_VerizonWireless.com
> > > > >
> > > > > Fat City Network Services -- (858) 538-5051 FAX: (858)
> > >
> > > 538-5051
> > >
> > > > > San Diego, California -- Public Internet access /
> > > >
> > > > Mailing Lists
> > >
> > >
Hemant K Chitale
Now using Eudora Email. Try it !
My home page is : http://hkchital.tripod.com
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Hemant K Chitale INET: hkchital_at_singnet.com.sg 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Khedr, Waleed INET: Waleed.Khedr_at_FMR.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') 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).Received on Sun Aug 04 2002 - 15:43:20 CDT
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