Re: What does Page Layout version mean? (Was: Re: Reducing NUMERIC size for 8.3)

On Tuesday 19 June 2007 10:15, Tom Lane wrote:
> Zdenek Kotala <Zdenek(dot)Kotala(at)Sun(dot)COM> writes:
> > I'm little bit confused when we introduce new page layout version? I
> > expect that new version become with changes with pageheader, tuple
> > header or data encoding (varlen/TOAST ...). But in case when there is
> > new data type internal implementation, there was not reason to update
> > version (see inet/cidr between 8.1 -> 8.2). Can me somebody clarify this?
>
> Well, we've changed it when there was a benefit to an existing tool to
> do so. So far that's meant page header and tuple header changes. If
> we ever had a working in-place upgrade solution, I think we'd be willing
> to make the page version account for datatype format changes too.
>

FWIW pg_migrator is a pretty good swing at an in-place upgrade tool for
8.1->8.2. Unfortunately until the PGDG decides that in-place upgrade is a
constraint their willing to place on development, I see them a good
chicken/egg away from making it a continually usefull tool.

--
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL