On Wed, 2003-04-09 at 19:38, Martijn van Oosterhout wrote:
> On Wed, Apr 09, 2003 at 01:38:15PM +0200, Reiter, Oliver wrote:
[snip]
> So that when you crash you can still tell which tuples are valid. Consider:
>
> begin;
> update table set ...;
> *crash*
>
> After the update you have all the rows updated stored twice and no way to
> tell which one is the right one except for the xmin,xmax values and the list
> of commited transactions. So, these need to be stored on disk. Preferably
> with the tuple so you don't end up with problem of the system table getting
> out of sync with the data table when the disk lost one of the updates while
> the machine was dying.
And this is the "price" that the PG developers decided to pay when they
decided to use MVCC instead of some other scheme...
Maybe PG just isn't great at DW?
--
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| Ron Johnson, Jr. mailto:ron.l.johnson@cox.net |
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| "A C program is like a fast dance on a newly waxed dance floor |
| by people carrying razors." |
| Waldi Ravens |
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