Re: [PATCH] Space reservation v02

Simon Riggs escreveu:
> On Tue, 2009-01-27 at 13:06 +0100, Zdenek Kotala wrote:
>
>> Space reservation MUST TO be implemented if we
>> want to have 8.4->8.5 upgrade.
>
> Why not just add a few dummy columns onto each catalog table? If we need
> space to expand a row we can just drop one of the dummy columns from the
> new catalog definition.
>
The problem is: how much space do we need at each catalog table? Suppose that
after 2 releases we need x + 1 bytes per tuple but we only foresaw x bytes; so
we need to deprecate support for this version and advise DBA to run
pg_upgrade two times. I prefer a solution where we know beforehand the size
per tuple so when we're rewriting we could use this information to upgrade.

--
Euler Taveira de Oliveira
http://www.timbira.com/