Re: pg_migrator issue with contrib

Magnus Hagander <magnus@hagander.net> writes:
> Tom Lane wrote:
>> Magnus Hagander <magnus@hagander.net> writes:
>>>> Could pg_migrator detect usage of "objects" oids (data types in
>>>> relation, index opclass, ...) that are unknown to be in the standard
>>>> -core + contrib distribution, and quit trying to upgrade the cluster in
>>>> this case, telling the user his database is not supported?
>> 
>>> +1 on this.
>> 
>>> Or at least, have it exit and say "if you know that these things are
>>> reasonably safe, run pg_migrator again with --force" or something like that.
>> 
>> I don't think that anything in that line is going to be helpful.
>> What it will lead to is people mindlessly using --force (cf our
>> bad experiences with -i for pg_dump).  If you can't give a *useful*
>> ie trustworthy warning/error, issuing a useless one is not a good
>> substitute.
>
> Well, in that case, error out would be a better option than doing it and
> probably fail later. And have a --force option available, but don't
> suggest it.

My vote would go to detect and error out without recovering option. If
the tool is not able to handle a situation and knows it, I don't see
what would be good about it leting the user lose data on purpose.

The --force option should be for the user to manually drop his columns
and indexes (etc) and try pg_migrator again, which will stop listing
faulty objects but care about the now compatible cluster.

Restoring the lost data is not the job of pg_migrator, of course.

Regards,
-- 
dim