Re: ORA-15555 snapshot too old?

Grandjanny Jerome (LDG) wrote:
> > Friedel Hosenfeld <friedel_at_pz-oekosys.uni-kiel.d400.de> writes:
> > >Since some days ago the database export doesn't work,
> > >giving instead the message "ORA-01555: snapshot too old (rollback s
> > >segment too small)".
> <snip>
> We also have the same problem sometimes with a database of these
> dimensions :
> - 7 Gigs database / About 4 Gigs currently filled,
> - db_block_size = 8 K
> - Rollback segment : Initial 5 Megs, Next 10 Megs, Max Extents 505,
> Optimal 5 Megs
> So, theoretically, the rollback segment can increase up to 8 K * 505
> = About 4 Gigs.
> But we have the ORA-01555 error. Using sqldba and monitoring rollback,
> I see my rollback segment with current size = 42 Megs and highwater = 92
> Megs meaning (if I understand highwater) that the maximun size of the
> rollback segment was 92 Megs.
> So why couldn't it dynamically increase more than 92 Megs ?

I don't know, but I expereienced exactly this, i.e.

• plenty of space for rollback segment growth
• monitoring of rollback segments showed RBSs remained small
• ORA-01555 error.

We tried different sizing of rollback segments to no avail. In the end the developer re-coded the program !

I never got a satisfactory answer this.

Kevin.

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