On Wed, Dec 2, 2009 at 7:53 PM, Bruce Momjian <bruce@momjian.us> wrote:
>> At the moment it doesn't seem likely that pg_migrator is *ever* going
>> to support upgrading from 7.4 or 8.0 or 8.1 to any later version.
>
> Agreed.
The problem is that the development effort to migrate data that was
never designed to be migratable is completely out of scale from the
benefits. You can solve problems pg_migrator has much more easily and
with less damage to the code by putting the hooks into the server
rather than making pg_migrator muck about inside the data structures
fixing things.
For example to deal with the problem of dropped columns we could add
hooks to CREATE TABLE to allow pg_migrator to specify the physical
order of columns. To do it without modifying the server pg_migrator
has to play tricks by running updates against the catalog tables. And
there are worse problems than that -- toast tables would require
massive amounts of code in the new version to migrate but we found
some simple tweaks to the toast format which eliminate the whole
problem going forward.
--
greg
