[Zope] Options for handling concurrency?

[Brian Takashi Hooper]

Hi Tone,

I just recently solved a performance problem that was related to ZODB
lock contention due to a idiosyncrasy with an external method that was
causing writes to ZODB on every page view, for my top page... it
couldn't be anything like this, could it?  One easy way to check is to
look at the undo list, if there are lots of transactions by the
Anonymous user on pages that don't look like they should be getting
changed, that's a good heads up.

The DB is another possible bottleneck - I have been using Sybase, which
with the level 3 DA gives very good performance, I can have 20 or more
simultaneous, persistent connections open to the DB...  tuning the SQL,
as Martijn mentioned, is also important - I profiled ZSQL methods once
and for the stuff I tested, selects from the cache were over 100 times
faster than direct access to the database.

Hope you can solve your problem!

--Brian

On Sun, 27 Feb 2000 07:17:06 +0000
tony <tony.mcdonald@ncl.ac.uk> wrote:

> Hi all,
> One of my Zope sites is used by classes of students - up to 60 or so at a
> time. When they use the site the response time is really slow - they could
> be waiting minutes between clicks. The site uses ZSQL methods *extensively*
> and external methods. I realise that part of this problem is because of our
> Sun iron (2400 pystones - my *iMac* does 4400, and a PIII 500MHz does 5500),
> but as I can't get this site onto another box in the near future, I'm after
> other ideas.
> 
> Can anyone give me some pointers (even just rule of thumb) to improve the
> response time? I was going to set the threads to be something like 32, but
> I've read other posts suggesting that wouldn't help too much. Is there
> someway I can profile what's going on for example?
> 
> Any thought gratefully received.
> tone
> 
> 
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