Re: Commit visibility guarantees

On Mon, May 18, 2009 at 05:18:06PM -0500, Marsh Ray wrote:
> On Mon, May 18, 2009 at 4:53 PM, Ben Chobot <bench(at)silentmedia(dot)com> wrote:
> > On Mon, 18 May 2009, Marsh Ray wrote:
> >> Hello Everyone,
> >> I'm looking at an easy real-time application using PostgreSQL.
> > As I understand real-time applications, PostgreSQL is inherintly unsuited
> > for the task. There is absolutely no timing constraints on your queries, and
> > "large" sets of working data can sometimes spill to disk, which incurs the
> > obvious - but not always consistent - performance hit.
>
> Definitely true, but I don't think it's really the issue here. The app
> does have a hard real-time deadline, but the deadline is generally
> quite "easy" for such a system. Like any web app, there will be a hard
> deadline to meet before the browser times out, though the timeout
> value 60 or more seconds.

Even then it's not useful to class it as real-time; nothing "bad"
happens if you don't get a response before timeout the user just gets an
error message. Real-time applies when if you don't get a response the
plane crashes or a heart stops because the pacemaker hasn't put out a
signal in time.

--
Sam http://samason.me.uk/