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Re: Odoo Performance and concurrency locks

Graeme Gellatly
- 09/14/2015 17:33:43
Without stating the obvious

Why not just use the gapped sequences?  When we had this issue we switched over the high volume ones that didn't really matter like stock moves, pickings, manufacturing etc, maybe sale orders then split out into multiple sequences the ones that mattered by company or shop.  Its not like the gapped sequences are a big problem creating gaps all the time, in fact I've never noticed a single gap.

On Tue, Sep 15, 2015 at 7:37 AM, Shawn Varghese <> wrote:
Perhaps the issue I was referring to has been related to a concurrency with user login session. I am currently referring to a concurrency lock arising from the POS implementation in OpenERP 7. 

@Olivier Dony and OpnERP Master,
There are multiple POS machines which simultaneously validate orders or press validate in the gap of a few seconds. From what I have gathered from the logs, it seems that the lock arises when simultaneous transactions try to obtain a sequence number for the orders (which is a gapless sequence).

This causes a concurrency issue and the process is retried. But every now and then the random retry wait time that is generated is too short and hence does not give enough time for the lock to be released and eventually, the transaction just times out. It does not cause any issues in user experience, as the whole process takes place in the backend, but I wanted to tackle it before the issue escalates.

Increasing the wait time has produced visible improvements as the lock gets released before the retry, in most cases. But since it is not recommended, I will read through the suggestions mentioned here and try a different approach.

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