Re: 7.2.3?

Alvaro Herrera <alvherre@atentus.com> writes:
> What would that converter need:
> [snip]
> I think that should be enough for converting table files.  I'd like to
> experiment with something like this when I have some free time.  Maybe
> next year...

It's difficult to say anything convincing on this topic without a
specific conversion requirement in mind.

Localized conversions like 7.3's tuple header change could be done on a
page-by-page basis as you suggest.  (In fact, one reason I insisted on
putting in a page header version number was to leave the door open for
such a converter, if someone wants to do one.)

But one likely future format change for user data is combining parent
and child tables into a single physical table, per recent inheritance
thread.  (I'm not yet convinced that that's feasible or desirable,
I'm just using it as an example of a possible conversion requirement.)
You can't very well do that page-by-page; it'd require a completely
different approach.
        regards, tom lane