| From: | Craig Ringer <ringerc(at)ringerc(dot)id(dot)au> |
|---|---|
| To: | Thomas Kellerer <spam_eater(at)gmx(dot)net> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: 9.2 and index only scans |
| Date: | 2012-08-28 13:04:58 |
| Message-ID: | 503CC1FA.9050905@ringerc.id.au |
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| Lists: | pgsql-general |
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
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