On Wed, Aug 31, 2016 at 10:52 AM, Josh Berkus <josh@agliodbs.com> wrote:
> On 08/30/2016 06:51 PM, Michael Paquier wrote:
>> On Wed, Aug 31, 2016 at 10:45 AM, Josh Berkus <josh@agliodbs.com> wrote:
>>> On 08/30/2016 06:39 PM, Michael Paquier wrote:
>>>> On Wed, Aug 31, 2016 at 10:35 AM, Josh Berkus <josh@agliodbs.com> wrote:
>>>>> ??? It's always been possible for me to give multiple standbys the same
>>>>> name, making a de-facto group.
>>>>
>>>> A "group" grammar, by that I mean an alias referring to a set of
>>>> nodes, is not supported. And you can still define multiple entries
>>>> with the same name.
>>>>
>>>
>>> Yeah, so what happens in the case I described? Is the master just
>>> looking for that number of commits, or is it looking for a commit from
>>> g1 and from g2?
>>
>> How do you set up synchronous_standby_names in this case? Are multiple
>> nodes using the same application_name, being either 'g1' or 'g2'?
>>
>
> Correct.
If my memories are correct, we'd wait for the nodes connected,
matching the name, and marked as 'sync' because the nodes connected
having the same name have the same priority rank. If there are other
nodes connected with the same name but have a higher priority the
potential ones are ignored.
> The other question I have is: presumably if s2 does not respond within
> a certain amount of time, it times out and is marked "disconnected", no?
Yes that depends on when the master node is aware of that.
> So the main way this is inferior to true quorum commit is that (a) we
> wait for that and (b) if s2 is busy but not unresponsive, we wait
> forever. No?
Even on previous versions we'd wait in this case. This is not new, and
this class of problems is expected to be solved at some degree with
the quorum patch that's listed in the first CF of 10 actually.
--
Michael