Thread: pg_dump and diffrent sizes

pg_dump and diffrent sizes

From
Maciej Piekielniak
Date:
Hello pgsql-sql,

I dump db with pg_dump v.8.1.3 on database postgresql server 7.4.7.
Data directory with my db on pg 7.4.7 had 1,8GB and
file with dump had 2,7GB.
Database have blob fields.

When I restore db on pg 8.1 - data directory have only 1GB, why?

-- 
Best regards,Maciej                          mailto:piechcio@isb.com.pl



Re: pg_dump and diffrent sizes

From
Scott Marlowe
Date:
On Fri, 2006-03-03 at 14:10, Maciej Piekielniak wrote:
> Hello pgsql-sql,
> 
> I dump db with pg_dump v.8.1.3 on database postgresql server 7.4.7.
> Data directory with my db on pg 7.4.7 had 1,8GB and
> file with dump had 2,7GB.
> Database have blob fields.
> 
> When I restore db on pg 8.1 - data directory have only 1GB, why?

I would guess that you have lots of highly compressible text entries,
and postgresql is compressing them for you.  The difference in size
between 7.4 and 8.1 is likely due to unrecycled tuples in the data
store.  Even with regular vacuuming, some small percentage of dead
tuples is normal.