Le Sun, 16 Oct 2011 16:45:30 +0200,
Cédric Krier <[email protected]> a écrit :

> On 12/10/11 12:13 +0200, Cédric Krier wrote:
> > Hi,
> > 
> > With the version 9.1 of PostgreSQL, the Serializable Isolation
> > Level [1] has been completly implemented. As the documentation
> > explains, application that uses this level must manage to replay
> > the transaction in case of conflict and this is the purpose of the
> > patch [2]. But I'm wondering if this isolation level is not to
> > strict for us. I think the Repeatable Read Isolation Level is
> > enough as we lock tables for some specific actions like for stock
> > assignation etc.


The documentation for Repeatable Read Isolation [1] tells: 

"""
Note: Prior to PostgreSQL version 9.1, a request for the Serializable
transaction isolation level provided exactly the same behavior
described here. To retain the legacy Serializable behavior, Repeatable
Read should now be requested.
"""

So this means that the patch linked hereunder will keep the current
behaviour with Postgresql 9.1 (and of course also for previous
versions).

[1] http://www.postgresql.org/docs/9.1/static/transaction-iso.html


> > As an example, I'm able to produce concurrency
> > exception when creating parties on PostgreSQL 9.1.
> > I think for performance, we must switch to Repeatable Read (also
> > other backend doesn't have the serializable isolation level).
> > 
> > What do you think about?
> 
> http://codereview.tryton.org/151006
> 


-- 
Bertrand Chenal

B2CK SPRL
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