Re: [PATCH 10/16] Introduce the concept that wal has a 'origin' node

Andres Freund <andres@2ndquadrant.com> writes:
> On Monday, June 18, 2012 11:51:27 PM Daniel Farina wrote:
>> What's the cost of going a lot higher?  Because if one makes enough
>> numerical space available, one can assign node identities without a
>> coordinator, a massive decrease in complexity.

> It would increase the size of every wal record. We just have 16bit left there
> by chance...

"Every WAL record"?  Why in heck would you attach it to every record?
Surely putting it in WAL page headers would be sufficient.  We could
easily afford to burn a page switch (if not a whole segment switch)
when changing masters.

I'm against the idea of eating any spare space we have in WAL record
headers for this purpose, anyway; there are likely to be more pressing
needs in future.
        regards, tom lane