Oliver Elphick writes:
> I never have understood why the basic table structure changes so much
> that it can't be read; just what is involved in getting the ability to
> read old versions?
The problem in an extensible system such as PostgreSQL is that virtually
every feature change is reflected by a change in the structure of the
system catalogs. It wouldn't be such a terribly big problem in theory to
make the backend handle these changes, but you'd end up with a huge bunch
of
if (dataVersion == 1) do this;
else if (dataVersion == 2) do that;
...
which would become slow and unwieldy, and would scare away developers.
That would of course be a self-serving scheme, because if the development
progress slowed down, you would have to update less frequently.
--
Peter Eisentraut peter_e@gmx.net
