Re: Performance of pg_dump on PGSQL 8.0

Out of curiosity, does anyone have any idea what the ratio of actual
datasize to backup size is if I use the custom format with -Z 0 compression
or the tar format?

Thanks.

On 6/14/06, Scott Marlowe <smarlowe(at)g2switchworks(dot)com> wrote:
>
> On Wed, 2006-06-14 at 09:47, John E. Vincent wrote:
> > -- this is the third time I've tried sending this and I never saw it get
> > through to the list. Sorry if multiple copies show up.
> >
> > Hi all,
>
> BUNCHES SNIPPED
>
> > work_mem = 1048576 ( I know this is high but you should see some of our
> > sorts and aggregates)
>
> Ummm. That's REALLY high. You might want to consider lowering the
> global value here, and then crank it up on a case by case basis, like
> during nighttime report generation. Just one or two queries could
> theoretically run your machine out of memory right now. Just put a "set
> work_mem=1000000" in your script before the big query runs.
>
> > We're inserting around 3mil rows a night if you count staging, info, dim
> > and fact tables. The vacuum issue is a whole other problem but right now
> > I'm concerned about just the backup on the current hardware.
> >
> > I've got some space to burn so I could go to an uncompressed backup and
> > compress it later during the day.
>
> That's exactly what we do. We just do a normal backup, and have a
> script that gzips anything in the backup directory that doesn't end in
> .gz... If you've got space to burn, as you say, then use it at least a
> few days to see how it affects backup speeds.
>
> Seeing as how you're CPU bound, most likely the problem is just the
> compressed backup.
>

--
John E. Vincent
lusis(dot)org(at)gmail(dot)com