[ic] mod_interchange and Apache MaxClients

[Kevin Walsh]

jeff at hisgirlfridays.com wrote:
> On Wed, Nov 16, 2005 at 12:32:25PM -0800, Ron Phipps wrote:
> > > to use a UNIX-domain socket file, rather than an Inet socket.  All of
> > > the websites I've worked with have used UNIX domain socket files.  It
> > > could be the case that the Inet needs some fine tuning.  It would be
> > > interesting to see if the same problem occurs when socket files are in
> > > use.
> > >
> I've experienced the problem with both unix domain and TCP.  I've
> actually had the problem for years.  The frequency with which it occurs
> is load-dependant on my system.
> 
I've never seen anything like what has been described in this thread.

The only way I can think to reproduce the problem (and I haven't tried
this) is as follows:

    1. Create a page that takes ages to display, but doesn't take
       long enough for IC to notice and hammer it.

    2. Flood the server with requests for that page.

    3. Sit back and wait for the request queue to fill.

       Requests that are waiting in the queue will look as if they are
       hanging.  Stopping and resubmitting the requests will probably
       just make matters worse.

Here's another test to add to the list:

When everything appears to pause, block port 80 at the firewall for a
little while.  Remove the block and check whether the backlog has been
cleared and IC is responding once again.  If this test succeeds then
the problem is flood/backlog related.  If not then, well, it was worth
a try.

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