Re: [COMMITTERS] pgsql: Keep track of transaction commit timestamps

On 10/12/14 16:03, Petr Jelinek wrote:
> On 10/12/14 04:26, Michael Paquier wrote:
>> On Thu, Dec 4, 2014 at 9:26 PM, Heikki Linnakangas
>> <hlinnakangas(at)vmware(dot)com> wrote:
>>> Yeah, it was raised. I don't think it was really addressed. There was
>>> lengthy discussion on whether to include LSN, node id, and/or some other
>>> information, but there was no discussion on:
>>>
>>> * What is a node ID?
>>> * How is it used?
>>> * Who assigns it?
>>>
>>> etc.
>>>
>>> None of those things are explained in the documentation nor code
>>> comments.
>>>
>
>>
>> Could it be possible to get a refresh on that before it bitrots too
>> much or we'll simply forget about it? In the current state, there is
>> no documentation able to explain what is the point of the nodeid
>> stuff, how to use it and what use cases it is aimed at. The API in
>> committs.c should as well be part of it. If that's not done, I think
>> that it would be fair to remove this portion and simply WAL-log the
>> commit timestamp its GUC is activated.
>
> I have this on my list so it's not being forgotten and I don't see it
> bitrotting unless we are changing XLog api again. I have bit busy
> schedule right now though, can it wait till next week? - I will post
> some code documentation patches then.
>

Hi,

as promised I am sending code-comment patch that explains the use of
commit timestamps + nodeid C api for the conflict resolution, comments
welcome.

--
Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services