Re: diskspace usage recovered on db rebuild

On Apr 1, 2005 9:21 AM, David Link <dlink(at)soundscan(dot)com> wrote:
> Greetings worthymen.
>
> I have a question regarding filesystem disk space usage.
>
> We have a production database containing 5 years of sales data.
> Linux 2.6.5; Postgresq 7.4.7. VACUUM ANALZYE the entire database
> everynight (about 40min).
> It's size, @SUM(pg_class.relpages) * 8192K, is ...
>
> About 66 Gigabytes on disk.
>
> When I rebuild the database (using pg_dump and pgsql ), the new
> resultant database is ..
>
> About 48 Gigabytes on disk.
>
> A 27% space savings.
>
> Can someone tell me why that is?

Are you doing a vacuum full each night? What is the specific
command(s) that you are using for vacuum, pg_dump and the import?

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