On 25/11/2007, Pablo Alcaraz <[EMAIL PROTECTED]> wrote: > > Tom Lane wrote: > > "Peter Childs" <[EMAIL PROTECTED]> writes: > > > >> On 25/11/2007, Erik Jones <[EMAIL PROTECTED]> wrote: > >> > >>>> Does the pg_dump create this kind of "consistent backups"? Or do I > >>>> need to do the backups using another program? > >>>> > >>> Yes, that is exactly what pg_dump does. > >>> > >>> > >> Yes so long as you are using transactions correctly. Ie doing a begin > before > >> each invoice and a commit afterwards if your not bothering and using > auto > >> commit you *may* have problems. > >> > > > > I think you need to qualify that a bit more. What you're saying is that > > if an application has consistency requirements that are momentarily > > violated during multi-statement updates, and it fails to wrap such > > updates into a single transaction, then pg_dump could capture one of the > > intermediate states. That's true, but it's hardly pg_dump's fault. > > If there were a system crash partway through such a sequence, the > > consistency requirements would be violated afterwards, too. > > > > > > Agree. In my case I define "consistent database state" like the state > the database has when the program that use it is stopped normally and > without errors. In this "state" the program starts without troubles and > "everything looks fine". I believe this behavior is because all the > inserts and updates are made using transactions. Another things will be > a bug, it ll be fixed and it ll not be pg_dump fault. > > So if pg_dump can capture a "consistent state" with all the data until > the start time, without all the pending open transaction updates/inserts > in the same way that I did when I stopped the program before start > pg_dump, for me is usefull and enough to solve my problem. > > Thanks to all! > > Pablo > > Given your long description over what you though was "constant" I thought it important that the answer yes but was given rather than just a plain yes. I've met quite a few apps that create inconstant databases when the database its self is actually consistent.
Peter
