Re: pg_dump estimation

In response to Allan Kamau <allank(at)sanbi(dot)ac(dot)za>:

> Sam Mason wrote:
> > On Tue, Jun 24, 2008 at 11:13:14PM -0500, Marcelo Martins wrote:
> >
> >> is there a way to find out / calculate / estimate how big a pg_dump
> >> using plain text format for a DB will be ?
> >>
> >
> > How about simply doing:
> >
> > pg_dump | wc -c
> >
> >
> > Sam
> >
> >
> Hi Marcelo,
>
> If (using Sam's suggestion) the reported size of bytes is larger than
> (or even close to) the current free space, you may want to plug in an
> external drive (USB or otherwise) and mount it, then do the dump to it.
>
> If you intend to upgrade postgreSQL to 8.3.3, I think it may be
> advisable to first install postgreSQL 8.3.3 hopefully from source as you
> can have more control on where the executable will be placed (the idea
> is to avoid at least initially overwriting the current executables for
> postgres you have already deployed) use the --prefix=/your/path option
> to facilitate isolated installation. Then use pg_dump (or pg_dumpall) of
> the new postgreSQL installation to take the dump. In simpler words, use
> 8.3.x pg_dump to make a dump of a running instance of postgreSQL 7.x for
> later restore on postgreSQL 8.3.x.

Also, you can probably use CLUSTER to get the DB size down to something
manageable. If you CLUSTER one table at a time, you can probably start
with the smaller tables and free up enough room to CLUSTER the larger
tables.

--
Bill Moran
Collaborative Fusion Inc.
http://people.collaborativefusion.com/~wmoran/

wmoran(at)collaborativefusion(dot)com
Phone: 412-422-3463x4023