Re: Synchronous replication

On Sun, Aug 1, 2010 at 9:51 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> Perhaps someone will claim that nobody wants to do that anyway (which
> I don't believe, BTW), but even in simpler cases it would be nicer to
> have an explicit policy rather than - in effect - inferring a policy
> from a soup of GUC settings.  For example, if you want one synchronous
> standby (A) and two asynchronous standbys (B and C).  You can say
> quorum=1 on the master and then configure vote=1 on A and vote=0 on B
> and C, but now you have to look at four machines to figure out what
> the policy is, and a change on any one of those machines can break it.
>  ISTM that if you can just write synchronous_standbys=A on the master,
> that's a whole lot more clear and less error-prone.

Some standbys may become master later by failover. So we would
need to write something like synchronous_standbys=A on not only
current one master but also those standbys. Changing
synchronous_standbys would require change on all those servers.
Or the master should replicate even that change to the standbys?

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center