Perrin Harkins wrote:
> Greg Stark wrote:
> > For example, it makes it very hard to mix any kind of long running query with
> > OLTP transactions against the same data, since rollback data accumulates very
> > quickly. I would give some appendage for a while to tell Oracle to just use
> > the most recent data for a long running query without attempting to rollback
> > to a consistent view.
>
> I believe setting the isolation level for dirty reads will allow you to
> do exactly that.
Oh, silly me. Oracle doesn't appear to offer dirty reads. The lowest
level of isolation is "read committed" which reads all data that was
committed at the time the query began, but doesn't preserve that state
for future queries. So, if you have lots of uncommitted data or you
commit lots of data to the table being queried while the query is
running you could make your rollback segment pretty big. But, if you
can afford Oracle, you can afford RAM.
- Perrin
