Re: 9.2 and index only scans

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 can see that making sense for index-oriented tables, but otherwise ...
ugh.

--
Craig Ringer