44 messages in org.postgresql.pgsql-hackersRe: New feature request: FlashBack Query| From | Sent On | Attachments |
|---|---|---|
| RPK | Feb 17, 2007 6:49 am | |
| Joshua D. Drake | Feb 17, 2007 7:50 am | |
| Tom Lane | Feb 17, 2007 8:48 am | |
| elein | Feb 17, 2007 4:06 pm | |
| Chad Wagner | Feb 17, 2007 4:43 pm | |
| Joshua D. Drake | Feb 17, 2007 7:21 pm | |
| Chad Wagner | Feb 17, 2007 7:49 pm | |
| Tom Lane | Feb 17, 2007 9:31 pm | |
| Warren Turkal | Feb 17, 2007 10:46 pm | |
| Hannu Krosing | Feb 18, 2007 1:45 pm | |
| Joshua D. Drake | Feb 18, 2007 2:27 pm | |
| Andreas 'ads' Scherbaum | Feb 19, 2007 1:53 am | |
| Hannu Krosing | Feb 19, 2007 4:36 am | |
| Florian G. Pflug | Feb 19, 2007 6:13 am | |
| Alvaro Herrera | Feb 19, 2007 6:27 am | |
| Zeugswetter Andreas ADI SD | Feb 19, 2007 6:32 am | |
| Zeugswetter Andreas ADI SD | Feb 19, 2007 6:38 am | |
| Florian G. Pflug | Feb 19, 2007 6:59 am | |
| Gregory Stark | Feb 19, 2007 7:18 am | |
| tom...@tuxteam.de | Feb 19, 2007 8:18 am | |
| August Zajonc | Feb 19, 2007 10:09 am | |
| Florian G. Pflug | Feb 19, 2007 11:30 am | |
| August Zajonc | Feb 19, 2007 12:00 pm | |
| Tom Lane | Feb 19, 2007 7:39 pm | |
| Jonah H. Harris | Feb 19, 2007 8:53 pm | |
| Gregory Stark | Feb 20, 2007 12:58 am | |
| RPK | Feb 20, 2007 3:25 am | |
| Andrew Dunstan | Feb 20, 2007 4:42 am | |
| Jonah H. Harris | Feb 20, 2007 7:19 am | |
| Rod Taylor | Feb 20, 2007 7:42 am | |
| Hannu Krosing | Feb 20, 2007 8:02 am | |
| Gregory Stark | Feb 20, 2007 8:28 am | |
| August Zajonc | Feb 20, 2007 8:39 am | |
| RPK | Feb 20, 2007 10:27 am | |
| Tom Lane | Feb 20, 2007 10:40 am | |
| Theo Schlossnagle | Feb 20, 2007 10:45 am | |
| Jonah H. Harris | Feb 20, 2007 11:48 am | |
| Jonah H. Harris | Feb 20, 2007 12:03 pm | |
| August Zajonc | Feb 20, 2007 7:30 pm | |
| Csaba Nagy | Feb 21, 2007 1:17 am | |
| Florian G. Pflug | Feb 21, 2007 6:01 am | |
| Alvaro Herrera | Feb 21, 2007 6:13 am | |
| Florian G. Pflug | Feb 21, 2007 7:08 am | |
| August Zajonc | Mar 1, 2007 9:48 am |
| Subject: | Re: New feature request: FlashBack Query | |
|---|---|---|
| From: | Joshua D. Drake (jd...@commandprompt.com) | |
| Date: | Feb 17, 2007 7:21:28 pm | |
| List: | org.postgresql.pgsql-hackers | |
Chad Wagner wrote:
On 2/17/07, elein <ele...@varlena.com> wrote:
For other recent time travel ideas see: http://www.varlena.com/GeneralBits/122.php Time travel is not cheap, though.
I am sure this topic has probably been beaten to death in the past, but has anyone talked about the advantages of Oracle's MVCC model versus PostgreSQL's MVCC model? Oracle achieves multiversioning by using rollback/undo segments, where PostgreSQL appears to place (essentially) the undo in the same space as the table.
My understanding is that the main difference is that rollbacks are inexpensive for us, but expensive for Oracle. Talk to an Oracle DBA about their Rollback logs :0.
However, they don't have vacuum, we do.
Joshua D. Drake
If I were to guess this is probably a major thing to change. Clearly there are advantages to both, with Oracle essentially the space consumed by a modified row is immediately available for reuse and generally there is little row migration assuming there is enough space on the block so you should be able to avoid updates to the index and the bloating that seems to go along with vacuuming.
Is there any previous discussions that folks could point out here?
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