Re: Support for N synchronous standby servers - take 2

On 2015-06-26 PM 02:59, Amit Langote wrote:
> On 2015-06-26 AM 12:49, Sawada Masahiko wrote:
>>
>> For example,
>> - s_s_name = '1(a, b), c, d'
>> The priority of both 'a' and 'b' are 1, and 'c' is 2, 'd' is 3.
>> i.g, 'b' and 'c' are potential sync node, and the quorum commit is
>> enable only between 'a' and 'b'.
>>
>> - s_s_name = 'a, 1(b,c), d'
>> priority of 'a' is 1, 'b' and 'c' are 2, 'd' is 3.
>> So the quorum commit with 'b' and 'c' will be enabled after 'a' down.
>>
>
> Do we really need to add a number like '1' in '1(a, b), c, d'?
>
> The order of writing names already implies priorities like 2 & 3 for c & d,
> respectively, like in your example. Having to write '1' for the group '(a, b)'
> seems unnecessary, IMHO. Sorry if I have missed any previous discussion where
> its necessity was discussed.
>
> So, the order of writing standby names in the list should declare their
> relative priorities and parentheses (possibly nested) should help inform about
> the grouping (for quorum?)
>

Oh, I missed Michael's latest message that describes its necessity. So, the
number is essentially the quorum for a group.

Sorry about the noise.

Thanks,
Amit