Re: [HACKERS] Hot Backup Ability - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] Hot Backup Ability
Date
Msg-id 199906300109.VAA03977@candle.pha.pa.us
Whole thread Raw
In response to Re: [HACKERS] Hot Backup Ability  (Michael Richards <miker@scifair.acadiau.ca>)
Responses Re: [HACKERS] Hot Backup Ability
Re: [HACKERS] Hot Backup Ability
List pgsql-hackers
> 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.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


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