Re: [HACKERS] Hot Backup Ability

> On Tue, 29 Jun 1999, Duane Currie wrote:
> 
> > Anyway, version 6.5 apparently supports hot backups by using MVCC
> > to give a view of a consistent version of the database during a
> > pg_dump (http://postgresql.nextpath.com/doxlist.html  search for
> 'backup')
> Hrm. Nothing pops out.
>     
> Just out of curiosity, I did a DUMP on the database while running a script
> that ran a pile of updates. When I restored the database files, it was so
> corrupted that I couldn't even run a select. vacuum just core dumped...

When you say DUMP, you mean pg_dump, right?  Are you using 6.5?

> If I can just run pg_dump to back it up, how does this guarantee any sort
> of referential integrity? Also during such a dump, it seems that things   
> block while waiting for a lock. This also happens during a pg_vacuum. I   
> thought that mvcc was supposed to stop this...

OK, sounds like you are using pg_dump, and 6.5.  pg_vacuum still blocks,
but pg_dump shouldn't.  This sounds unusual.  You should have gotten
everything at the time of the _start_ of the dump.

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