From: | Sean Chittenden <sean(at)chittenden(dot)org> |
---|---|
To: | Gavin Sherry <swm(at)linuxworld(dot)com(dot)au> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: LISTEN/NOTIFY benchmarks? |
Date: | 2003-04-30 01:26:04 |
Message-ID: | 20030430012604.GB94932@perrin.int.nxad.com |
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Thread: | |
Lists: | pgsql-hackers |
> > > I'm not an expert on signals, not even a novice, so I might be
> > > totally off base, but it seems like the Async Notification
> > > implementation does not scale. If it does not, does anyone have
> > > a solution for the problem of signalling a each event in a
> > > possibly very large set of events to a large number of clients?
> >
> > <brainfart_for_the_archives> Hrm.... I should see about porting
> > kqueue/kevent as a messaging buss for the listen/notify bits to
> > postgresql... that does scale and it scales well to tens of
> > thousands of connections a second (easily over 60K, likely closer
> > to 1M is the limit).... </brainfart_for_the_archives>
>
> Except that it is FreeBSD specific -- being system calls and all --
> if I remember correctly. If you're going to move to a system like
> that, which is a good idea, best move to a portable system.
You can #ifdef abstract things so that select() and poll() work if
available. Though now that I think about it, a queue that existed
completely in userland would be better... an shm implementation that's
abstracted would be ideal, but shm is a precious resource and can't
scale all that big. A shared mmap() region, however, is much less
scarce and can scale much higher. mmap() + semaphore as a gate to a
queue would be ideal, IMHO.
I shouldn't be posti^H^H^H^H^Hrambling though, haven't slept in 72hrs.
:-/ *stops reading email* -sc
--
Sean Chittenden
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