[Zope] Zope performance and memory usage (SybaseDAv2, too)

[Hung Jung Lu]

>On Fri, 7 Apr 2000, John Morton wrote:
> > Most of that memory is actually shared between the threads, so the
> > size of one thread is closer to your real memory usage.

Is this a factual statement or is it a conjecture? I
used the Unix command "top" to see the memory usage, and
each thread was occupying a physical memory size of 23 MB
(before I restarted and packed Zope.)

After I restarted and packed Zope, it's started to take
about 7MB and slowly increased now taking up 12 MB,
each thread. The previous boot up of Zope has been running
for about a week, so I still can't guarantee it won't
climb up again to 23 MB.

> > A lot of that memory usage will be cached objects, cached Sybase
> > queries, and the Gadfly database, which is kept in memory.

Oops, just as I am typing this message, after accessing another
table in Sybase, the memory usage went up to 14 MB.

So I think the Sybase queries are definitely the ones to blame.
My SybaseDAv2 adapter has been REALLY SLOW, too, about 0.3 sec
per query. So I think there is either some inefficiency or
memory leak in SybaseDAv2.

Arrghh... why would SybaseDAv2 take up the task of caching
queries result? This does not make a lot of sense.... The
database server should be the one caching results, not the
adapter...

> > Try
> > flushing Zope's cache and packing it after a restart to see what the
> > 'base' memory usage should be.

Thanks. It was 7 MB, about the size of Data.fs.

> > Everything else will be cache (unless
> > there really is some hitherto unknown memory leak!).

Probably memory leak in Sybase adapter... I seem to remember
someone mentioned this before (?), not sure, though. I will
dig in some more.

>There must be. If one is lucky and the Zope process doesn't crash for a
>long timeone will find that the process takes way more memory than (thread
>number)xData.fs size. I have seen it with many Zope installations even
>with very simple ones.

thanks,

Hung Jung

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