On Tue, Aug 28, 2012 at 6:04 AM, Craig Ringer <ring...@ringerc.id.au> wrote:
> On 08/28/2012 05:51 PM, Thomas Kellerer wrote: > >> Martijn van Oosterhout, 28.08.2012 10:02: >> >>> I'm not sure how oracle avoids the same issues: >>> - The index has no visibility information, so you can't tell if an >>> index entry refers to a row you can actually see in your session. >>> The visibility map might help here in the future. >>> >> >> In Oracle an index (entry) has the information about transactional >> visibility. >> > > Wow. Doesn't that mean that indexes are insanely expensive to update, > since each index (and possibly also the table its self) needs updating? > I was thinking of read performance. But it might be a case where the global optimization might be worth the local cost. I don't know. Best Wishes, Chris Travers
