openerp-community team mailing list archive

[Leonardo Pistone <leonardo.pistone@xxxxxxxxxxx>]

Dear Eric,

I didn't have time to investigate, so that might not be relevant, but I've
seen this commit on 6.1 recently:

http://bazaar.launchpad.net/~openerp/openobject-server/6.1/revision/4337

Leonardo


On Wed, May 15, 2013 at 11:55 AM, Eric Caudal <eric.caudal@xxxxxxxxxxxxxx>wrote:

>  Hi,
> We have a case where our procurement scheduler (with procurement_confirm
> and action_assign) is blocking other transactions (such as website
> synchronization) or vice versa with an error such as "Serialized Access due
> to concurrent update".
> So far we have made some researches and we discover that this is maybe due
> to an error " Repeatable Read Isolation Level", documented here:
> http://www.postgresql.org/docs/9.2/static/transaction-iso.html
>
> A simple case would be like this:
>
> Session1: BEGIN;
> Session2: BEGIN;
> Session1: SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
> Session2: SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
> Session1: SELECT * FROM tunnels WHERE un = 1 FOR UPDATE;
>  un | password
> ----+----------
>   1 | bugsy
> (1 row)
>
> Session1: UPDATE tunnels SET password = 'malone' WHERE un = 1;
> Session2: SELECT * FROM tunnels WHERE un = 1 FOR UPDATE;
> ...waits on Session1's lock...
> Session1: COMMIT;
> Session2: ERROR:  could not serialise access due to concurrent update
>
> In current OpenERP code, we have check and there are 3 main places where
> this kind of transactions are used:
> base/res_users.py for function login, line 334,
> stock/stock.py, for function  _product_reserve line 442
> stock_prodlot_wizard/prodlot_wizard, class stock_move_split_lines_exist,
> line 279
>
> My questions:
> 1. Is it something mandatory in standard code? What if we by pass/modify
> them
> 2. Would it be an option to commit more often?
> 3. Is there any other reason why we could have this concurrent update?
>
> Suggestions are more than welcome!
>
> --
>
> Eric Caudal*CEO*
> --*Elico Corporation, Shanghai branchOpenERP Premium Certified Training Partner *
> Cell: + 86 186 2136 1670
> Office: + 86 21 6211 8017/27/37
> Skype: elico.corperic.caudal@elico-corp.comhttp://www.elico-corp.com
>
> [image: Elico Corp]
>
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