| Rollback Segments [message #61625] |
Tue, 11 May 2004 20:20  |
shesha
Messages: 24
Registered: August 2003
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Junior Member |
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Hi,
We are getting ORA-1555 error in export.
Export is scheduled to run daily. We are not getting this error every time the export is done..but it is coming once in a while..
We have kept the minextents as '2' for all RBS. Can we increase this to say '20' for eliminating ORA-1555 error?
If yes then how?
can we use 'Alter RBS .....Storage (Minextents 20); ?
If I try to give above statement then it is giving error as
ERROR at line 1:
ORA-01570: MINEXTENTS must be no larger than the 4 extents currently allocated.
Can you please suggest an alternative
Thanks in advance
Sheshadri
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| Re: Rollback Segments [message #61626 is a reply to message #61625] |
Tue, 11 May 2004 20:44  |
Daljit Singh
Messages: 290
Registered: October 2003
Location: Texas
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Senior Member |
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Hi,
First of all tell us which DB version u r using? and what r the extents sizes in ur DB? MINEXTENTS doesn't has any link with this error.
Upto 8i by increasing the extent sizes u can eliminate this error. But u can't change INTITIAL & MINEXTENTS parameters for any segment. Moreover increasing the MINEXTENTS will not help u to solve this problem it will just increase the performance of RBS extens allocation. And if u want to increase that also bcz the value 2 for minextents is not adequate according to me than u have to recreate the RBS. In short u have to have some large extents in ur RBS to eliminate this error and instead of changing MINEXTENTS recreate the
RBS with high INITIAL and NEXT values.
And in 9i u can use auto undo management feature in which by setting a proper value for UNDO_RETENTION u can eliminate this problem.
Daljit.
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| Re: Rollback Segments [message #61634 is a reply to message #61626] |
Tue, 11 May 2004 22:37 |
shesha
Messages: 24
Registered: August 2003
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Junior Member |
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Hi,
Thanks for the reply.
I have two databases, one running in 8.0.5 and other in 8.1.7.
I am getting error in both DB's.
For first one 8.0.5, I have 7 RBS (Apart from SYS).
6 RBS have Initial and Next as 16M. and one have 32M.
All RBS have Minextent as 2 and Maxextent as 505.
Extents have not gone beyond 42
For Second one 8.1.7, I have 22 RBS (Apart from SYS).
13 RBS have Initial and Next as 8M. and remaining have 32M.
All RBS have Minextent as 2 and Maxextent as 249.
Extents have not gone beyond 17
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| Re: Rollback Segments [message #61638 is a reply to message #61634] |
Tue, 11 May 2004 23:06 |
Daljit Singh
Messages: 290
Registered: October 2003
Location: Texas
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Senior Member |
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Hi,
Well the sizes of RBS are ok for a normal DB. Now the only thing is when u take export of ur DB? As u said that u dont get this error every time so it means there are some other huge transactions runs when u take export. That transaction change the data and after that ur export search the before images of that data in RBS and when it unable to find the same in RBS then it throw that error.
You should schedule the export at some off time means when the workload on the server is minimum. If u need 24 X 7 availability then u can schedule it when the workload on the server is minimum like at night before or after any batch runs as per the requirements. But if 24 X 7 availability is not required then u can take export after opnening the DB in restricted mode.
Moreover if consistency is not an issue then u can use CONSISTENT = N while exporting.
Daljit Singh.
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