Re: Why ORA-1555 snapshot too old.

From: Chuck <chuckh_at_softhome.net>
Date: Tue, 29 Oct 2002 09:59:53 -0500
Message-ID: <apm7pc$2tubm$1@ID-85580.news.dfncis.de>

"Alex Filonov" <afilonov_at_yahoo.com> wrote in message

news:336da121.0210280802.46b934f5_at_posting.google.com...

> "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.

There's a number of things I'd like to see Oracle reveal but they won't. The exact content of rollback entries is one of them. I'd also like to see an explanation of the hashing algorithms too so you could presort data according to the algorithm when loading a hash table. If my experience with another hashing databases is any indication, it would speed up loads 10x - 20x. Received on Tue Oct 29 2002 - 08:59:53 CST