Re: standby registration (was: is sync rep stalled?)

On Mon, Oct 4, 2010 at 3:25 PM, David Christensen <david(at)endpoint(dot)com> wrote:
>
> On Oct 4, 2010, at 2:02 PM, Robert Haas wrote:
>
>> On Mon, Oct 4, 2010 at 1:57 PM, Markus Wanner <markus(at)bluegap(dot)ch> wrote:
>>> On 10/04/2010 05:20 PM, Robert Haas wrote:
>>>> Quorum commit, even with configurable vote weights, can't handle a
>>>> requirement that a particular commit be replicated to (A || B) && (C
>>>> || D).
>>>
>>> Good point.
>>>
>>> Can the proposed standby registration configuration format cover such a
>>> requirement?
>>
>> Well, if you can name the standbys, there's no reason there couldn't
>> be a parameter that takes a string that looks pretty much like the
>> above.  There are, of course, some situations that could be handled
>> more elegantly by quorum commit ("any 3 of 5 available standbys") but
>> the above is more general and not unreasonably longwinded for
>> reasonable numbers of standbys.
>
>
> Is there any benefit to be had from having standby roles instead of individual names?  For instance, you could integrate this into quorum commit to express 3 of 5 "reporting" standbys, 1 "berlin" standby and 1 "tokyo" standby from a group of multiple per data center, or even just utilize role sizes of 1 if you wanted individual standbys to be "named" in this fashion.  This role could be provided on connect of the standby is more-or-less tangential to the specific registration issue.
>

Big +1 FWIW.

--
Mike Rylander