Re: DRAFT 9.6 release - Mailing list pgsql-advocacy

From Josh Berkus
Subject Re: DRAFT 9.6 release
Date
Msg-id d516774d-f9fa-56fd-33d8-4940a883a4fd@agliodbs.com
Whole thread Raw
In response to DRAFT 9.6 release  (Josh Berkus <josh@agliodbs.com>)
Responses Re: DRAFT 9.6 release  (Michael Paquier <michael.paquier@gmail.com>)
List pgsql-advocacy
On 08/30/2016 07:09 PM, Michael Paquier wrote:
> 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.

So, if we had:

2 ( g1, g2, g3 )

where each of g1, g2 and g3 were three replicas with the same name

then if two of the replicas from g1 ack'd the commit would proceed, even
though no replica from g2 has?

there's a big difference in utility depending on the answer to this, and
I don't have any good way to set up a test case.

--
--
Josh Berkus
Red Hat OSAS
(any opinions are my own)


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