[Zope] zope2.2.0 and what is high load

[Chris McDonough]

> i went to each Zeo client control_panel, and see that there's 
> a mzximum of 
> four connections open at any given time.

OK, I'm not sure this is real meaningful.  A lot can happen in between
refreshes.  This is only a rough sort of "realtime" guess of what's
going on.

> why wouldn't increasing the number of threads with -t25 
> affect the way zope 
> behave?  do i need to change it in z2.py?

No... -t[whatever] does the same thing as NUMBER_OF_THREADS in z2.py.

> > There is also a profiling facility inside 
> Control_Panel/debug that does
> > some sort of automated performance compilation for you, though I've
> > never had a reason to use it.  When it's running, it also 
> purportedly
> > slows Zope down quite a bit.
> >
> 
> profiling is not enabled since i dont really know the heck it does.

I don't know what it does specifically, either.  I've never needed to
use it.  Maybe somebody else can comment.

> > I suggest that you:
> >
> > 1) Monitor your Zope clients' thread usages by using their debug
> > facilities.
> done.  as mentioned above, the number of connections is four 
> at most.  what 
> else should i look for in the debugInfo?

That's about it for your problem.  Maybe the profiling stuff can give
more info, I'm not sure.
 
> most of the z2 threads are used, although only 3-4 are used 
> heavily.  what 
> does this show?

It shows that four threads have database connections.  I'm curious as to
why you're only seeing four threads being served by database connections
too.

You may want to ramp your number of threads down to 5 (-t5).  25 doesn't
do much for you because only 7 threads can be using database connections
at any given time.  The high number of threads you're servicing might
actually be slowing things down as they contend for available database
connections.

Why are you frontending this with apache?  how are you servicing two ZEO
clients via a single apache?  Does it do some sort of round-robining?
Or does each box have its own apache?  Is there any reason you're not
just using straight ZServer?  I'm wondering if apache processes
contending to talk to available Zope python threads might be slowing
stuff down?

It doesn't seem as if bumping your number of database connections will
do us any good here, because it doesn't seem you're using all 7.  I'm
not sure *why* you're not using all 7, because you've got at least 15
processes waiting around just on your top screen for DB connections.
Maybe manage_debug isn't telling you the whole story, or maybe you
caught it at a low-load period.  I wonder if the profiling stuff would
help here.

Maybe someone else can jump in here, this is all I can think of at the
moment.