Re: Commit visibility guarantees

On Mon, May 18, 2009 at 4:53 PM, Ben Chobot <bench@silentmedia.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.

There is a near-instantaneous context switch from the 'update' process
to the 'select' process, and I am wondering if some behaviors change
with that tight scheduling.

- Marsh