[Zope-DB] mysql concurrency

[mkur at gazeta.pl]

Hi,

I've got problems with my zope app that is highly depended on a mysql
database.

The application is two-tier with mysql connections over
GE. Performance is OK but it seems it has problems with concurrency.
ZMySQLDA is not able to maintain more then 2 connections at the same
time. With increasing load each request is effectively waiting for it's
connection and responses become really slow ...

I know it's a known problem. I'm sure all components are thread-safe
(checked it manually). I also run zope with 10 threads and mysql server
with 10 threads too. But it does not help much.

Does anyone know how it can be improved ?
Is it possible zope connection object instances number could have
influence in here ?

And please do not ask me to move to Postgres ... No, I'm not after
flamewar in here ;-)

Versions info:

Python: 2.3.3
Zope: 2.7.0
MySQLdb: 0.9.2
ZMySQLDA: 2.0.8 (with Chris Withers patch applied)
Mysql server: 3.23.58 on Linux 2.4.26
Mysql client: 4.0.18 on Solaris9 (64-bit)

Thanks,