Re: Why ORA-1555 snapshot too old.

"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message news:<apclm6$ghm$1$8300dec7_at_news.demon.co.uk>...
> I think you need to be a little more careful about how
> you describe this. The rollback segment does not
> get 'copies of database blocks' written into it, it get
> copies of the bits of rows that have been changed.

Agreed,

Strictly speaking, rollback segment gets "rollback entries" written into it, not database blocks. Sometimes I'd wish the structure of these entries is described in the documentation.

>
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>
> Jonathan Lewis
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> Alex Filonov wrote in message
> <336da121.0210230800.467dfcc4_at_posting.google.com>...
> >The problem here is that rollback segment gets overwritten before
> select
> >statement finishes. This happens besause every transaction creates
> undo copy of
> >the database block. If you have many small transactions, you have
> many undo

> >copies of database blocks. You can also have many undo copies of the
> same block.
Received on Mon Oct 28 2002 - 10:02:56 CST