Re: Support for N synchronous standby servers - take 2

On Fri, Jun 26, 2015 at 5:04 PM, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>
> Hi,
>
> On 2015-06-25 PM 01:01, Michael Paquier wrote:
>> On Thu, Jun 25, 2015 at 12:57 PM, Fujii Masao wrote:
>>> On Thu, Jun 25, 2015 at 12:15 PM, Michael Paquier wrote:
>>>> and that's actually equivalent to that in
>>>> the grammar: 1(AAA,BBB,CCC).
>>>
>>> I don't think that they are the same. In the case of 1(AAA,BBB,CCC), while
>>> two servers AAA and BBB are running, the master server may return a success
>>> of the transaction to the client just after it receives the ACK from BBB.
>>> OTOH, in the case of AAA,BBB, that never happens. The master must wait for
>>> the ACK from AAA to arrive before completing the transaction. And then,
>>> if AAA goes down, BBB should become synchronous standby.
>>
>> Ah. Right. I missed your point, that's a bad day... We could have
>> multiple separators to define group types then:
>> - "()" where the order of acknowledgement does not matter
>> - "[]" where it does not.
>
> For '[]', I guess you meant "where it does."

Yes, thanks :p
--
Michael