Bruce Momjian <bruce@momjian.us> writes:
> Tom Lane wrote:
>> I've spent some time thinking about possible workarounds for this, and
>> not really come up with any. The only feasible thing I can think of
>> to do is teach pg_migrator to refuse to migrate if (a) the old DB
>> contains contrib/isn, and (b) the new DB has FLOAT8PASSYVAL (which
>> can be checked in pg_control). One question here is how you decide
>> if the old DB contains contrib/isn. I don't think looking for the
>> type name per se is a hot idea. The best plan that has come to mind
>> is to look through pg_proc to see if there are any C-language functions
>> that reference "$libdir/isn".
> Sure, pg_migrator is good at checking. Please confirm you want this
> added to pg_migrator.
Yeah, I'd suggest it. Even if we later come up with a workaround for
contrib/isn, you're going to want to have the infrastructure in place
for this type of check, because there will surely be cases that need it.
Note that I think the FLOAT8PASSYVAL check is a must. There is no
reason to forbid migrating isn on 32-bit machines, for example.
regards, tom lane