Re: Does VACUUM ever free up any disk space?

On Thu, 11 Sep 2003, Chris Miles wrote:

> I've read a lot where people recommend using VACUUM FULL
> to free up disk space, especially after many updates/inserts.
>
> But does a regular VACUUM (or VACUUM ANALYSE) ever free up
> any space?
>
> 24/7 production databases cannot be locked for long periods
> of time to run VACUUM FULL, but I do not want data files
> growing indefinitely (any more than they need to) so I hope
> the routine VACCUM ANALYSE will take care of this.
>
> My pg is version 7.2.x but the question can apply to newer
> versions as well if the functionality has changed.

A regular vacuum since 7.2 never actually frees up space, it simply marks
the space in the file as available for reuse. Note that in many
circumstances this is actually better than freeing up the space, as it
allows the database to store date without having to extend and possibly
fragment the table.