Re: upgrading postgres version

On Fri, Oct 23, 2009 at 4:26 PM, Anj Adu <fotographs(at)gmail(dot)com> wrote:
> All our postgres versions are 8.1.x..... pg_migrator supports only 8.2
> and above..

We used slony to migrate from 8.1 to 8.3 flawlessly. The nice this is
it let us run the 8.3 database as a slave, where we could point x% of
traffic to it to see how it was working, and spot major problems (we
had exactly two bits of code to fix regarding casting dates to text
that needed fixing anyway).

After a week of testing, we could simply throw the switch and go to
8.3 as the main db. Sequence of events were roughly:

shutdown app layer
run slony failover command
edit config to point to the old db as the main db and vice versa
startup app layer
paint system green to prevent rust

That last step is entirely optional.