Re: pg_dump, MVCC and consistency

Beleive me, when you get data feeds with bad data and you have to do each
insert as an xact because copy will just dump out, you can hit 1bil really
fast.

Alex

On 10/24/05, Martijn van Oosterhout <kleptog(at)svana(dot)org> wrote:
>
> On Mon, Oct 24, 2005 at 11:25:00AM -0600, Michael Fuhr wrote:
> > PostgreSQL 8.1 makes checks to avoid data loss due to transaction
> > ID wraparound, but there's one situation I'm not sure how it handles:
> > when a transaction is so long-lived that it would appear to be in
> > the future of newly-created transactions due to wraparound. I'd
> > have to dig into the source code to find out if that's possible,
> > and if so, what happens. Maybe one of the developers will comment.
>
> To avoid this you need to do a VACUUM FULL over the database at least
> once every two billion transactions (not statements or tuples,
> transactions). To that end, the server begins complaining after one
> billion. I've never seen this in practice. Perhaps you could calculate
> how long it would take to do that many transactions. Most systems will
> never see it...
>
> Hope this helps,
> --
> Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> > tool for doing 5% of the work and then sitting around waiting for
> someone
> > else to do the other 95% so you can sue them.
>
>
>