Re: pg_stat_replication log positions vs base backups

On Thu, Nov 26, 2015 at 10:53 PM, Magnus Hagander <magnus@hagander.net> wrote:
> On Thu, Nov 26, 2015 at 1:03 PM, Michael Paquier <michael.paquier@gmail.com>
> wrote:
>>
>> On Thu, Nov 26, 2015 at 6:45 PM, Magnus Hagander wrote:
>> > I'm only talking about the actual value in pg_stat_replication here, not
>> > what we are using internally. These are two different things of course -
>> > let's keep them separate for now. In pg_stat_replication, we explicitly
>> > check for InvalidXLogRecPtr and then explicitly set the resulting value
>> > to
>> > NULL in the SQL return.
>>
>> No objections from here. I guess you already have a patch?
>
> Well, no, because I haven't figured out which way is the logical one - make
> them all return NULL or make them all return 0/0...

It seems to me that NULL is the logical one. We want to define a value
from the user prospective where things are in an undefined state.
That's my logic flow, other opinions are of course welcome.