Re: Synchronous replication - patch status inquiry

On Thu, 2010-09-02 at 15:15 +0300, Heikki Linnakangas wrote:
> On 02/09/10 15:03, Simon Riggs wrote:
> > On Thu, 2010-09-02 at 19:24 +0900, Fujii Masao wrote:
> >> On Wed, Sep 1, 2010 at 7:23 PM, Heikki Linnakangas
> >> <heikki.linnakangas@enterprisedb.com>  wrote:
> >>> That requirement falls out from the handling of disconnected standbys. If a
> >>> standby is not connected, what does the master do with commits? If the
> >>> answer is anything else than acknowledge them to the client immediately, as
> >>> if the standby never existed, the master needs to know what standby servers
> >>> exist. Otherwise it can't know if all the standbys are connected or not.
> >>
> >> Thanks. I understood why the registration is required.
> >
> > I don't. There is a simpler design that does not require registration.
> >
> > Please explain why we need registration, with an explanation that does
> > not presume it as a requirement.
> 
> Please explain how you would implement "don't acknowledge commits until 
> they're replicated to all standbys" without standby registration.

"All standbys" has no meaning without registration. It is not a question
that needs an answer.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Development, 24x7 Support, Training and Services