Re: big database resulting in small dump

Lonni J Friedman <netllama(at)gmail(dot)com> writes:
> On Fri, Jul 20, 2012 at 11:05 AM, Ilya Ivanov <forn(at)ngs(dot)ru> wrote:
>> I have a 8.4 database (installed on ubuntu 10.04 x86_64). It holds Zabbix
>> database. The database on disk takes 10Gb. SQL dump takes only 2Gb.

> Its not entirely clear what behavior you expect here. Assuming that
> you're referring to running pg_dump, then you should just about never
> expect the size of the resulting dump to be equal to the amount of
> disk space the database server files consume on disk. For example,
> when I pg_dump a database that consumes about 290GB of disk, the
> resulting dump is about 1.3GB. This is normal & expected behavior.

The fine manual says someplace that databases are commonly about 5X the
size of a plain-text dump, which is right in line with Ilya's results.
Lonni's DB sounds a bit bloated :-(, though maybe he's got an atypically
large set of indexes.

regards, tom lane