On Thursday 09 August 2001 22:17, Greg Ames wrote:
> > Known issues with 2.0.23:
> >
> > 1) Win9x, WinME, and Netware do not yet work.
> > 2) Unix: The threaded MPM might take longer than expected to perform
> > a graceful restart if an insufficient number of incoming requests
> > are being received at the time of the restart.
>
> Sorry I missed it when you first wrote this, but the sentence above
> isn't stricly true, and I believe it may be causing some folks to be
> overly alarmed about threaded.
>
> Graceful restarts happen just as quickly in threaded as with prefork, as
> far as parsing the config file, serving new http requests with the new
> config, and finishing old requests are concerned. The one and only
> thing that may take longer under low load conditions is cleaning up idle
> threads and their processes from the old generation. I don't consider
> that much of a concern, especially since any new requests help resolve
> the situation.
Greg, I'm sorry, but this is just not true. Please take a look at the code. The
way that graceful restarts work in the threaded mode, is that we accept the
connection, serve the request, and then shutdown the thread. Since threads
serve a request before they are shutdown, having them sitting around means that
the graceful restart hasn't been finished yet. It also means that a site could be
serving pages with the old config long after the graceful restart was signalled.
Yes, on a heavily hit server, this is much less of an issue, but it doesn't go
away, because we rely on the OS to ensure that every thread get's its fair
share of requests.
> As you know from personal experience, you can do several graceful
> restarts per second with threaded in 2.0.23, without problems.
Try doing graceful restarts on a server that isn't being hit continuosly. If you
think this case doesn't matter, consider slashdot, and what will happen if you
are running a server that is usually very quiet, but you believe that you will be
being hit very hard soon. Most people would re-config their server, and do a
graceful restart to handle the load they fear. With the threaded MPM, the first
set of requests will be served with the old config instead of the new one.
I have been on site at a user who wanted to re-config their server everyday at
3:00pm, because they always got a big spike from 3:00 - 5:00, as people got
ready to leave the office at the end of the day. At other times, they didn't have the
same load, so they wanted the server to use less resources. With today's threaded
MPM, I couldn't say to them that their server would only finish the current requests
with the old config, and all new requests would be served with the new config.
Ryan
_____________________________________________________________________________
Ryan Bloom [EMAIL PROTECTED]
Covalent Technologies [EMAIL PROTECTED]
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