On Mon, Apr 26, 2004 at 12:53:09PM -0600, Guy Fraser wrote:I realize that one you vacuum you can no longer time travel to before the vacuum. Although I never tried to use it, I thought time travel was a feature in PostGreSQL. My understanding of the time travel feature was to allow a query to be processed with 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 may be.
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.
Thank you for the update, I will not use time travel in further explanations of transactional integrity.:-)
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