Re: Move postgresql_fdw_validator into dblink

Shigeru HANADA <shigeru(dot)hanada(at)gmail(dot)com> writes:
> (2012/10/09 0:30), Kohei KaiGai wrote:
>> If it is also OK for you, I'd like to take over this patch to comitter.
>> This patch is prerequisite of postgresql_fdw, so I hope this patch
>> getting merged soon.

> Please go ahead. :-)

While reviewing this patch, I realized that we can't just summarily
delete the built-in postgresql_fdw_validator function: if we do, any
existing foreign-data wrapper definitions that depend on it will fail
to load into 9.3 servers. This would at least cause problems during
pg_upgrade for anyone who has set up dblink foreign servers according
to the current recommendation.

So I think we can't remove that functionality just yet. What we could
do is adjust postgresql_fdw_validator to throw a WARNING that it's
deprecated. This wouldn't prevent it from being used during dump/reload
scenarios, but it would put people on notice that the code will be
removed eventually. Without such a warning, it's not clear that we'll
ever be able to remove it without getting complaints.

However, I'm not sure where that leaves us with respect to the original
goal of getting rid of use of that function name. Thoughts?

For the moment I'm going to commit just the dblink changes in the patch,
and leave the core code alone pending agreement on what to do about the
upgrade-path issue.

regards, tom lane