Re: Issues with Quorum Commit

On Fri, Oct 8, 2010 at 5:10 PM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> Do we really need that?

Yes. But if there is no unsent WAL when the master goes down,
we can start new standby without new backup by copying the
timeline history file from new master to new standby and
setting recovery_target_timeline to 'latest'. In this case,
new standby advances the recovery to the latest timeline ID
which new master uses before connecting to the master.

This seems to have been successful in my test environment.
Though I'm missing something.

> I don't think that's acceptable, we'll need to fix
> that if that's the case.

Agreed.

> You can cross timelines with the archive, though. But IIRC there was some
> issue with that too, you needed to restart the standbys because the standby
> scans what timelines exist at the beginning of recovery, and won't notice
> new timelines that appear after that?

Yes.

> We need to address that, apart from any of the other things discussed wrt.
> synchronous replication. It will benefit asynchronous replication too. IMHO
> *that* is the next thing we should do, the next patch we commit.

You mean to commit that capability before synchronous replication? If so,
I disagree with you. I think that it's not easy to address that problem.
So I'm worried about that implementing that capability first means the miss
of sync rep in 9.1.

Regards,

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