Re: No heap lookups on index

On Thu, 2006-01-19 at 09:18 +0800, Christopher Kings-Lynne wrote:
> > Oracle does, but you pay in other ways. Instead of keeping dead tuples
> > in the main heap, they shuffle them off to an 'undo log'. This has some
> > downsides:
> >
> > Rollbacks take *forever*, though this usually isn't much of an issue
> > unless you need to abort a really big transaction.
>
> It's a good point though. Surely a database should be optimised for the
> most common operation

Yes.

> - commits, rather than rollbacks?

Commits are most common because most databases are optimized for them.
Lots of programs go through a ton pre-checking to avoid a rollback that
they don't need to do under PostgreSQL.

I've found that for small systems I tend to rely very heavily on
frequent vacuums and database level exceptions for virtually all data
checking. Rollbacks are nearly as common as commits in those
environments if not more-so.
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