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Thread: pg_start_backup without WAL archiving

pg_start_backup without WAL archiving

From
Peter Eisentraut
Date:
Why is it not allowed to call pg_start_backup when WAL archiving is off?
Wouldn't this be useful as a discrete file system backup without PITR
capability?

--
Peter Eisentraut
http://developer.postgresql.org/~petere/

Re: pg_start_backup without WAL archiving

From
"Jeff Larsen"
Date:
On Nov 25, 2007 8:24 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
> Why is it not allowed to call pg_start_backup when WAL archiving is off?
> Wouldn't this be useful as a discrete file system backup without PITR
> capability?

Because a file system level backup is no good unless the database is
stopped, or you are using PITR.

Re: pg_start_backup without WAL archiving

From
Peter Eisentraut
Date:
Jeff Larsen wrote:
> On Nov 25, 2007 8:24 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
> > Why is it not allowed to call pg_start_backup when WAL archiving is off?
> > Wouldn't this be useful as a discrete file system backup without PITR
> > capability?
>
> Because a file system level backup is no good unless the database is
> stopped, or you are using PITR.

You are begging the question.  If I enable WAL archiving, make a base backup
to a safe place, and my data center goes up in flame immediately afterwards
without a WAL segment being archived, that base backup should still be
usable.  Or maybe not.  That's the question.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/

Re: pg_start_backup without WAL archiving

From
Tom Lane
Date:
Peter Eisentraut <peter_e@gmx.net> writes:
> Jeff Larsen wrote:
>> Because a file system level backup is no good unless the database is
>> stopped, or you are using PITR.

> You are begging the question.  If I enable WAL archiving, make a base backup
> to a safe place, and my data center goes up in flame immediately afterwards
> without a WAL segment being archived, that base backup should still be
> usable.  Or maybe not.  That's the question.

And the answer is still "no".  If you don't have the entire series of
WAL files made over the period of the base backup, you're out of luck.

            regards, tom lane

Re: pg_start_backup without WAL archiving

From
Simon Riggs
Date:
On Sun, 2007-11-25 at 15:24 +0100, Peter Eisentraut wrote:
> Why is it not allowed to call pg_start_backup when WAL archiving is off?
> Wouldn't this be useful as a discrete file system backup without PITR
> capability?

I'm submitting a patch today that better describes PITR facilities for
making a standalone backup.

--
  Simon Riggs
  2ndQuadrant  http://www.2ndQuadrant.com