Re: 7.3.4 on Linux: UPDATE .. foo=foo+1 degrades massivly

Alvaro Herrera wrote:

>On Mon, Apr 26, 2004 at 12:53:09PM -0600, Guy Fraser wrote:
>
>
>
>>Eventually the automatic purging of  'stale' data will be supported,
>>but hopefully it will be configurable to allow 'time travel' when
>>required, and allow for a reasonable time to be able to roll back
>>transactions.
>>
>>
>
>Well, you are saying two different things here: to garbage-collect
>automatically the database (rather than by manual VACUUMs), and to be
>able to UNDO transactions, effectively going back in time.
>
>The former is likely to be supported in some not-too-distant future,
>maybe hopefully the next release; the latter is not even planned, and in
>the past it has been disregarded as too costly.  Not implementation
>time cost, mind you, but runtime cost.
>
>
I realize that one you vacuum you can no longer time travel to before the vacuum. Although I never tried to use it, I
thoughttime travel was a feature in PostGreSQL. My understanding of the time travel feature was to allow a query to be
processedwith the data set as it was at a previous time. Since I did not have need for that feature fro any of the   
projects I have been involved in, I did not check to see how it worked, or followed it's development or demise as it
maybe. 

Thank you for the update, I will not use time travel in further explanations of transactional integrity.:-)