could not serialize access due to concurrent update while creating pos picking from a job
It could have obtained the lock, as the lock is currently available.  But it had been locked at some previous point which overlaps with the current transaction's snapshot.  So obtaining the lock is possible, but would create a serialization problem if it were to acquire it.  Reporting that as a serialization failure seems like the correct outcome.
Using FOR UPDATE NOWAIT in a transaction with elevated isolation level seems inconsistent, or at least unnecessary.  What are you hoping to accomplish by doing this?  Your description of "while creating pos picking from a job" doesn't elucidate this for me.  Is that some odoo-specific jargon?
Impacted versions:
12.0
Steps to reproduce:
I have made a customization to postpone the creation of pos order picking
and delegate the task to a job
some time i get the error below
Current behavior:
2020-06-18 17:49:24,588 1370 ERROR cafe9.rabeh.io odoo.addons.base.models.ir_cron: Call from cron POS Orders: Process Pending Orders for server action #610 failed in Job #24
Traceback (most recent call last):
File "/opt/rabeh/odoo/odoo/addons/base/models/ir_cron.py", line 102, in _callback
self.env['ir.actions.server'].browse(server_action_id).run()
File "/opt/rabeh/odoo/odoo/addons/base/models/ir_actions.py", line 569, in run
res = func(action, eval_context=eval_context)
File "/opt/rabeh/odoo/odoo/addons/base/models/ir_actions.py", line 445, in run_action_code_multi
safe_eval(action.sudo().code.strip(), eval_context, mode="exec", nocopy=True)  # nocopy
allows to return 'action'
File "/opt/rabeh/odoo/odoo/tools/safe_eval.py", line 350, in safe_eval
return unsafe_eval(c, globals_dict, locals_dict)
File "/opt/rabeh-12/rabeh_addons/pos_pending_session/models/pos_order.py", line 68, in pending_picking_creation
po_order.create_picking()
File "/opt/rabeh-12/rabeh_addons/pos_pending_session/models/pos_order.py", line 36, in
create_picking
res = super(PosOrder, orders).create_picking()
File "/opt/rabeh/odoo/addons/point_of_sale/models/pos_order.py", line 841, in create_picking
order._force_picking_done(order_picking)
File "/opt/rabeh/odoo/addons/point_of_sale/models/pos_order.py", line 856, in _force_picking_done
picking.action_done()
File "/opt/rabeh/odoo/addons/stock/models/stock_picking.py", line 631, in action_done
todo_moves._action_done()
File "/opt/rabeh/odoo/addons/purchase_stock/models/stock.py", line 96, in _action_done
res = super(StockMove, self)._action_done()
File "/opt/rabeh/odoo/addons/stock_account/models/stock.py", line 389, in _action_done
res = super(StockMove, self)._action_done()
File "/opt/rabeh/odoo/addons/stock/models/stock_move.py", line 1137, in _action_done
moves_todo.mapped('move_line_ids')._action_done()
File "/opt/rabeh/odoo/addons/stock/models/stock_move_line.py", line 445, in _action_done
Quant._update_available_quantity(ml.product_id, ml.location_dest_id, quantity, lot_id=ml.lot_id, package_id=ml.result_package_id, owner_id=ml.owner_id, in_date=in_date)
File "/opt/rabeh/odoo/addons/stock/models/stock_quant.py", line 216, in _update_available_quantity
self._cr.execute("SELECT 1 FROM stock_quant WHERE id = %s FOR UPDATE NOWAIT", [quant.id], log_exceptions=False)
File "/opt/rabeh/odoo/odoo/sql_db.py", line 148, in wrapper
return f(self, *args, **kwargs)
File "/opt/rabeh/odoo/odoo/sql_db.py", line 225, in execute
res = self._obj.execute(query, params)
psycopg2.errors.SerializationFailure: could not serialize access due to concurrent update
Expected behavior:
i think this line should generate could not obtain lock
i was just wondering when it could generate "could not serialize access due to concurrent update"