[Zope] zope performance issues

[Chris McDonough]

On Wed, 2004-05-19 at 03:20, Trevor Warren wrote:
> Hello Chris,
> 
>  50 users, short circuit(no sql), 1 iteration per
> user, test duration 15mins. Threads are 10 and DB
> connections are 25.

FWIW, not really a big deal, but you have approximately 14 DB
connections sitting around not doing much except potentially consuming
some meory, you can probably bump the number of DB connections down to
11 or so for 10 threads and get the same results.

>  Will add DB Cache in next
> iteration.

Right.

>  Test progressing well until 7th minute. hits/sec
> fallen to <50 from 250/sec and resp times gone up
> dramatically. TPS is at 25+ currently for the set of
> 50 users.

No idea what this could be.  I still don't know what a transaction is to
you, so TPS doesn't mean much to me.  hits/sec does, though, and having
the hitrate drop by 200 hits a second sounds very suspicious.  I'd make
sure your test rig is doing what you think it's doing.

Benchmarking is tricky.  Usually I'll try to "prime" the server before
trying any benchmarking.  I'll start up the server and do a test run
first before timing anything.  That populates all of the caches and
whatnot so I'm not measuring any initialization overhead.  I've also
found that sometimes it's the test *client* that is at fault for strange
results (like, not generating enough requests to saturate the server). 
I suspect that may be the problem in your setup.

- C