Speaking of this trick with a txn in each RBS, I've got a shell script on my
website (http://www.evdbt.com/tools.htm) that does just that.  It is named
"prevent1555.sh" which uses a stored procedure created by a SQL script named
"prevent1555_ddl.sql"...

As Jared mentioned, it is kind of a last resort, but it works...




on 6/4/03 4:05 PM, [EMAIL PROTECTED] at [EMAIL PROTECTED] wrote:

> .. and if it still doesn't work, use the trick of putting a transaction
> in
> each of the rollback segments while the system is otherwise quiesced,
> and *do not* commit or rollback the transactions.
> 
> This forces the rollbacks to extend if necessary, they will never wrap
> back to the first extent ( actually the second) as long as those
> transactions
> are not committed.
> 
> It just uses a lot of disk space.  Disk is cheap, right?  :)
> 
> Consider offlining all your production RBS and creating temporary ones
> that you can easily drop later.
> 
> I've used it with SAP client copies, which will not run to completion
> without
> doing this, at least on our system.
> 
> Jared
> 
> 
> 
> 
> 
> Kirtikumar Deshpande <[EMAIL PROTECTED]>
> Sent by: [EMAIL PROTECTED]
> 06/04/2003 09:45 AM
> Please respond to ORACLE-L
> 
> 
>       To:     Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
>       cc: 
>       Subject:        Re: Snapshot too old during stress test... how to avoid
> 
> 
> Try removing optimal setting, and shrinking RBS to the min extents (or
> even below) before running
> your tests. 
> 
> - Kirti 
> 
> 
> --- Garry Gillies <[EMAIL PROTECTED]> wrote:
>> From memory (of a course attended looong ago),
>> Oracle recommends one rollback segment for every
>> three to four users.
>> Four rollback segments between thirty six processes
>> does seem a little mean.
>> 
>> Garry 
>> 
>> 
>> 
>> 
>> 
>> <[EMAIL PROTECTED]>
>> Sent by: [EMAIL PROTECTED]
>> 04/06/03 13:59
>> Please respond to ORACLE-L
>> 
>> 
>>         To:     Multiple recipients of list ORACLE-L
> <[EMAIL PROTECTED]>
>>         cc: 
>>         Subject:        Snapshot too old during stress test... how to
> avoid
>> 
>> 
>> Im testing worst case scenarios right now. So Im doing batch
>> updates,inserts,deletes and 'create table as' from a staging tablespace
> of 
>> approximately 5GBs to a master tablespace of approximately 11GBs.
>> 
>> Ive got my job queue processes set to 36 and Im running 36 at a time in
>> the background in order to gather statistics and timing under worst case
> 
>> scenarios. 
>> 
>> Im in 8.1.7.3 and I have increased the size of my RBS tablespace to 11GB
> 
>> for this test. I have 4 standard RBS with optimal size set to 1GB. Why
>> would I get a snapshot too old? I would think that 11GBs of rollback
> would 
>> be big enough. Would increasing the number of Rollback segments avoid
> this 
>> even though I have the same amount of space in the tablespace?
>> 
>> In reality Im going to seriallize the process to avoid this and to
> improve 
>> performance, however, I want to stress the system.
>> 
>> any advice? 
>> 
>> -- 
>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
>> -- 
>> Author: <[EMAIL PROTECTED]
>>   INET: [EMAIL PROTECTED]
>> 
> 
> 
> 
> __________________________________
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Author: Tim Gorman
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