Re: NextXID format change (was Re: exposing pg_controldata and pg_config as functions)

On Sat, Feb 13, 2016 at 7:54 AM, Bruce Momjian <bruce@momjian.us> wrote:
> On Thu, Feb 11, 2016 at 07:18:46PM -0500, Bruce Momjian wrote:
>> No, that is not an improvement --- see my previous comment:
>>
>> > We could get more sophisticated by checking the catalog version number
>> > where the format was changed, but that doesn't seem worth it, and is
>> > overly complex because we get the catalog version number from
>> > pg_controldata, so you would be adding a dependency in ordering of the
>> > pg_controldata entries.
>>
>> By testing for '906', you prevent users from using pg_upgrade to go from
>> one catalog version of 9.6 to a later one.  Few people may want to do
>> it, but it should work.
>
> C comment added explaining why we do this.

Thanks for the addition.
-- 
Michael