| From: | "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com> |
|---|---|
| To: | "Thomas Kellerer" <spam_eater(at)gmx(dot)net> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: MVCC and index-only read |
| Date: | 2008-11-18 19:58:57 |
| Message-ID: | 36e682920811181158q6d712784t20d7465ac3601fac@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
On Tue, Nov 18, 2008 at 2:33 PM, Thomas Kellerer <spam_eater(at)gmx(dot)net> wrote:
> If all the columns from the select list are available in the index, then
> Oracle will always prefer the index scan over a table scan (at least I have
> never seen something else). Even for a SELECT that returns all rows of the
> table.
No, it doesn't always prefer index fast full scan.
> They are taking this concept even further with index organized tables, where
> no real "table data" exists, everything is stored in the index (quited nice
> for e.g. link tables that only consist of two or three integer columns)
Those are essentially clustered indexes, and they're not quite stored
exactly the same..
--
Jonah H. Harris, Senior DBA
myYearbook.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Jonah H. Harris | 2008-11-18 20:03:24 | Re: MVCC and index-only read |
| Previous Message | Scott Marlowe | 2008-11-18 19:57:17 | Re: MVCC and index-only read |