Hello,
Thank you for the update. Now the performance improved very much. But there is one issue when two or more people trying to do sale order confirmation simultaneously. The error message is given below.

Environment Information : 
System : Linux-2.6.38-8-generic-x86_64-with-Ubuntu-11.04-natty
OS Name : posix
Distributor ID:	Ubuntu
Description:	Ubuntu 11.04
Release:	11.04
Codename:	natty
Operating System Release : 2.6.38-8-generic
Operating System Version : #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011
Operating System Architecture : 64bit
Operating System Locale : en_IN.ISO8859-1
Python Version : 2.7.1+
OpenERP-Client Version : 6.0.2
Last revision No. & ID :0 null:
Traceback (most recent call last):
  File "/home/user/workspace/npg/bin/netsvc.py", line 489, in dispatch
    result = ExportService.getService(service_name).dispatch(method, auth, params)
  File "/home/user/workspace/npg/bin/service/web_services.py", line 599, in dispatch
    res = fn(db, uid, *params)
  File "/home/user/workspace/npg/bin/addons/audittrail/audittrail.py", line 538, in exec_workflow
    return super(audittrail_objects_proxy, self).exec_workflow(db, uid, model, method, *args, **argv)
  File "/home/user/workspace/npg/bin/osv/osv.py", line 122, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home/user/workspace/npg/bin/osv/osv.py", line 196, in exec_workflow
    res = self.exec_workflow_cr(cr, uid, obj, method, *args)
  File "/home/user/workspace/npg/bin/osv/osv.py", line 189, in exec_workflow_cr
    return wf_service.trg_validate(uid, obj, args[0], method, cr)
  File "/home/user/workspace/npg/bin/workflow/wkf_service.py", line 80, in trg_validate
    res2 = instance.validate(cr, id, ident, signal)
  File "/home/user/workspace/npg/bin/workflow/instance.py", line 48, in validate
    workitem.process(cr, witem, ident, signal, force_running, stack=stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 61, in process
    ok = _split_test(cr, workitem, activity['split_mode'], ident, signal, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 174, in _split_test
    _join_test(cr, t[0], t[1], ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 182, in _join_test
    create(cr,[activity], inst_id, ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 41, in create
    process(cr, res, ident, stack=stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 61, in process
    ok = _split_test(cr, workitem, activity['split_mode'], ident, signal, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 174, in _split_test
    _join_test(cr, t[0], t[1], ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 182, in _join_test
    create(cr,[activity], inst_id, ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 41, in create
    process(cr, res, ident, stack=stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 61, in process
    ok = _split_test(cr, workitem, activity['split_mode'], ident, signal, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 174, in _split_test
    _join_test(cr, t[0], t[1], ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 182, in _join_test
    create(cr,[activity], inst_id, ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 41, in create
    process(cr, res, ident, stack=stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 53, in process
    result = _execute(cr, workitem, activity, ident, stack)
  File "/home/user/workspace/npg/bin/workflow/workitem.py", line 107, in _execute
    wkf_expr.execute(cr, ident, workitem, activity)
  File "/home/user/workspace/npg/bin/workflow/wkf_expr.py", line 68, in execute
    return _eval_expr(cr, ident, workitem, activity['action'])
  File "/home/user/workspace/npg/bin/workflow/wkf_expr.py", line 58, in _eval_expr
    ret = eval(line, env, nocopy=True)
  File "/home/user/workspace/npg/bin/tools/safe_eval.py", line 284, in safe_eval
    return eval(test_expr(expr,_SAFE_OPCODES, mode=mode), globals_dict, locals_dict)
  File "", line 1, in <module>
  File "/home/user/workspace/npg/bin/osv/orm.py", line 181, in <lambda>
    return lambda *args, **argv: attr(self._cr, self._uid, [self._id], *args, **argv)
  File "/home/user/workspace/npg/bin/addons/sale/sale.py", line 674, in action_ship_create
    pick_name = self.pool.get('ir.sequence').get(cr, uid, 'stock.picking.out')
  File "/home/user/workspace/npg/bin/addons/base/ir/ir_sequence.py", line 97, in get
    return self.get_id(cr, uid, code, test='code')
  File "/home/user/workspace/npg/bin/addons/account/sequence.py", line 64, in get_id
    context=context)
  File "/home/user/workspace/npg/bin/addons/base/ir/ir_sequence.py", line 86, in get_id
    (sequence_id, company_id))
  File "/home/user/workspace/npg/bin/sql_db.py", line 78, in wrapper
    return f(self, *args, **kwargs)
  File "/home/user/workspace/npg/bin/sql_db.py", line 131, in execute
    res = self._obj.execute(query, params)
OperationalError: could not obtain lock on row in relation "ir_sequence"