concurrent access error with multi-proccessing

[Cuong]

Hi,

With multi-process, when I run update module sale (any other modules is the same), concurrent access error occurs.
Server Info: openerp-server 6.1, rev 4210
Web client: openerp-web-6.1, rev 2363
uwsgi 1.2.3: for running openerp application.
With gunicorn, I dont test yet.

Here is the log file:
===
2012-06-18 09:38:48,325 3159 ERROR uwsgi_01 openerp.sql_db: bad query: update ir_module_module set "website"='http://www.openerp.com',"maintainer"=NULL,"description"='
The base module to manage quotations and sales orders.
======================================================

Workflow with validation steps:
-------------------------------
    * Quotation -> Sales order -> Invoice

Invoicing methods:
------------------
    * Invoice on order (before or after shipping)
    * Invoice on delivery
    * Invoice on timesheets
    * Advance invoice

Partners preferences:
---------------------
    * shipping
    * invoicing
    * incoterm

Products stocks and prices
--------------------------

Delivery methods:
-----------------
    * all at once
    * multi-parcel
    * delivery costs

Dashboard for Sales Manager that includes:
------------------------------------------
    * Quotations
    * Sales by Month
    * Graph of Sales by Salesman in last 90 days
    * Graph of Sales per Customer in last 90 days
    * Graph of Sales by Product''s Category in last 90 days
    ',"contributors"=NULL,"sequence"=14,"auto_install"='False',"icon"='/sale/static/src/img/icon.png',"certificate"='0058103601429',"license"='AGPL-3',"author"='OpenERP SA',"application"='True',"complexity"='easy',"shortdesc"='Sales Management',write_uid=1,write_date=(now() at time zone 'UTC') where id IN (223)
Traceback (most recent call last):
  File "/opt/virtualenv/openerp/local/lib/python2.7/site-packages/openerp-6.1-py2.7.egg/openerp/sql_db.py", line 212, in execute
    res = self._obj.execute(query, params)
TransactionRollbackError: could not serialize access due to concurrent update
===

Thanks,