[Zope] Options for handling concurrency?

[Tony McDonald]

At 9:43 am +0100 27/2/00, Martijn Pieters wrote:
>
>- Have a look at /Control_Panel/manage_debug. It'll show you reference
>counts and currenlty open connections, which can be very helpful in
>targeting hotspots.

Aye carumba! - what a lot of information. I'm going to start delving 
around there and see what happens. Is there any additional 
documentation available on what the info. means? - I've looked in the 
ApplicationManager.py code is a wee bit over my head.

As an aside (to the list), looking around the ApplicationManager.py 
reveals something called manage_profile. It looks like the main Zope 
functions are being profiled here (ie not at the object level). It's 
interesting, but it does seem to be a resource hog...

>- Also, what DBMS are you using? If you are using a level 1 or 2 DA (see
>http://www.zope.org/Members/petrilli/DARoadmap) then you can do only one DB
>query at a time. It might be time to choose a different DB, or if you are
>using the old MySQL DA, to upgrade.

It's MySQL, but using the latest DA - I'm pretty sure I'm doing more 
than one query at a time as I set off a ZSQL query that takes 9 
seconds from the MySQL command line, and then started to use aspects 
of the site that I *know* use MySQL lookups. BTW, the 9 second SQL 
query isn't used in the site! :)

>- If you are using ZSQL a lot, do you use caching? Even a cache expiry of 1
>second would help a  heavily hit site tremendously, noone will notice the
>data returned being at most 1 second out of date.But all hits with equal
>parameters on the same thread in Zope within that second need only one DB
>query.

I do use caching Martijn, but I must admit that it's been a hit and 
miss affair. I'm trying to do as many of my SQL queries in external 
methods (ironically for the performance), so I may well be losing a 
lot of the caching performance breakthrough there .... hmmm. I wonder 
if I could do something like...


Thanks a lot for the pointers, I'll report back to the list if I come 
across anything really useful!
Tone
------
Dr Tony McDonald,  FMCC, Networked Learning Environments Project 
http://nle.ncl.ac.uk/
The Medical School, Newcastle University Tel: +44 191 222 5888
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