Horton

Re: Sync Rep v17

Simon Riggs <simon@2ndquadrant.com>

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From: Simon Riggs <simon@2ndQuadrant.com>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Fujii Masao <masao.fujii@gmail.com>, pgsql-hackers@postgresql.org, Daniel Farina <daniel@heroku.com>
Date: 2011-03-02T21:13:13Z
Lists: pgsql-hackers 
On Wed, 2011-03-02 at 15:44 -0500, Andrew Dunstan wrote:
> 
> On 03/02/2011 03:39 PM, Simon Riggs wrote:
> > Truly "synchronous" requires two-phase commit, which this never was. So
> > the absence or presence of the poorly specified parameter called
> > allow_standalone_primary should have no bearing on what we call this
> > feature.
> >
> 
> I haven't been following this very closely, but to me this screams out 
> that we simply must not call it "synchronous".

As long as we describe it via its characteristics, then I'll be happy:

* significantly reduces the possibility of data loss in a sensibly
configured cluster

* allow arbitrary N+k resilience that can meet and easily exceed
 "5 nines" data durability

* isn't two phase commit

* isn't a magic bullet that will protect your data even after your
hardware fails or is disconnected

-- 
 Simon Riggs           http://www.2ndQuadrant.com/books/
 PostgreSQL Development, 24x7 Support, Training and Services