[Zope] limits to connections to zserver

[Jamie Heilman]

Dieter Maurer wrote:
> Julian Gollop wrote at 2004-5-18 00:13 +0100:
> >What is the limit on the number of connections to zserver at any time? How
> >can I change this? How can I monitor this?
> 
> I think it is unlimited -- but may be wrong.

It is limited, asyncore.poll (patched, but same basic idea) is used by
default which uses select(2) which is of course limited to a set
number of file handles it can monitor.  But I very very much doubt
that in practice the select(2) limit will be a bottleneck, as Zope's
resource usage tends to swamp most machines long before you're seeing
significant penalties coming from select.  Now the limit on the number
of allowed connections is by default 1000, I think there's a config
variable you can tweak that with.  This is to say nothing of what the
gateway server you use is configured to support, but presumebly you'd
set the gateway server to allow a few less concurrent connections than
the ZServer settings itself, just to allow for a little slack.

My gut feeling is that if you even being approach 50 concurrent
connections[1] you'll need to move to a ZEO layout anyway, but its
going to depend a lot on the application you're serving.

As for monitoring it... it should log it, but it doesn't, but that
shouldn't be too hard to fix, just add a logging line in the accept()
handler or something.

-- 
Jamie Heilman                     http://audible.transient.net/~jamie/
"You came all this way, without saying squat, and now you're trying
 to tell me a '56 Chevy can beat a '47 Buick in a dead quarter mile?
 I liked you better when you weren't saying squat kid." -Buddy

[1] I totally pulled that number out of my ass, suffice it to say
    that for 90% of the common applications Zope's resource usage
    is going to be the deciding factor.