Re: synchronous_commit and remote_write

fOn Wed, May 09, 2012 at 03:02:23PM +0100, Simon Riggs wrote:
> On 9 May 2012 13:48, Robert Haas <robertmhaas@gmail.com> wrote:
> > On Wed, May 9, 2012 at 7:29 AM, Bruce Momjian <bruce@momjian.us> wrote:
> >> Let me point out that our documentation says nothing about it being
> >> written to the kernel --- it just says "has received the commit record
> >> of the transaction to memory."
> >
> > Maybe remote_receive would be better.  If we're actually writing it
> > back to the kernel before acknowledging the commit, that seems like an
> > implementation defect more than anything else, since it does not -
> > AFAICS - provide any additional, useful guarantee.
> 
> It does provide an additional guarantee, but I accept you personally
> may not find that useful.

The guarantee is that if Postgres crashes, we don't lose any data, but
not if the OS crashes (right?) because that isn't clear now.

> If the docs don't describe it well enough, then we can change the docs.

Well, we should make that clear in the docs then.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +