From: | David Fetter <david(at)fetter(dot)org> |
---|---|
To: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, Boszormenyi Zoltan <zb(at)cybertec(dot)at>, Dimitri Fontaine <dfontaine(at)hi-media(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Synchronization levels in SR |
Date: | 2010-09-08 14:38:47 |
Message-ID: | 20100908143847.GA4451@fetter.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Wed, Sep 08, 2010 at 03:22:46PM +0100, Simon Riggs wrote:
> On Wed, 2010-09-08 at 09:50 -0400, Robert Haas wrote:
>
> > So that means we have to make sure that none of the effects of a
> > transaction can be seen until WAL is fsync'd on the master AND the
> > slave has acked.
>
> Yes, that's right. And I like your example; one for the docs.
>
> There is a slight complexity there: An application might connect to
> the standby and see the changes made by the transaction, even though
> the master has not yet been notified, but will be in a moment. I
> don't see that as an issue though, but worth mentioning cos its just
> the "Byzantine Generals" problem.
For completeness, a reference to the aforementioned Byzantine
Generals: http://en.wikipedia.org/wiki/Byzantine_fault_tolerance
Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david(dot)fetter(at)gmail(dot)com
iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics
Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2010-09-08 14:44:43 | Re: git: uh-oh |
Previous Message | Magnus Hagander | 2010-09-08 14:27:27 | Re: git: uh-oh |