Re: postgresql storage and performance questions

On Tue, 2007-11-20 at 13:04 -0500, Josh Harrison wrote:
> On Nov 20, 2007 11:13 AM, Brad Nicholson <bnichols@ca.afilias.info> wrote:
> > On Tue, 2007-11-20 at 07:22 -0500, Josh Harrison wrote:
> >
> > > There were a couple of things we noted.
> > > 1. Tablesize twice as much than oracle-- Im not sure if postgres null
> > > columns has any overhead since  we have lots of null columns in our
> > > tables.Does postgresql has lots of overhead for null columns?
> >
> > Did you by any chance have an aborted load of the data?  If you load in
> > a table, and that load fails or does not commit, it will still occupy
> > the space until you vacuum.  If you try to load again, the table will be
> > twice the size.
> >
> > If you want to compact the physical space the table occupies, you can
> > try running VACUUM FULL on it, and possibly a redindex afterwards.  This
> > will bring the physical space down to the minimum.  Both of these
> > operations will lock out access to the tables though.
> I ran vacuum full on this table already. I haven't re-indexed it. But
> this will not affect the table size...right...since indexes are stored
> separately?

You are correct about the indexes.


--
Brad Nicholson  416-673-4106
Database Administrator, Afilias Canada Corp.