Re: Proposal for 9.1: WAL streaming from WAL buffers

On Fri, Jun 11, 2010 at 11:24 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> I think the failover case might be OK.  But if the master crashes and
> restarts, the slave might be left thinking its xlog position is ahead
> of the xlog position on the master.

Right. Unless we perform a failover in this case, the standby might go down
because of inconsistency of WAL after restarting the master. To avoid this
problem, walsender must wait for WAL to be not only written but also *fsynced*
on the master before sending it as 9.0 does. Though this would degrade the
performance, this might be useful for some cases. We should provide the knob
to specify whether to allow the standby to go ahead of the master or not?

Regards,

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