[Dbix-class] transaction isolation levels

Stanley Pilton stanley.pilton at gmail.com
Mon May 6 16:37:48 GMT 2013


On Mon, May 6, 2013 at 3:52 PM, Peter Rabbitson <rabbit+dbic at rabbit.us> wrote:
> On Mon, May 06, 2013 at 03:28:30PM +0100, Stanley Pilton wrote:
>>
>> To provide the SQL illustration more generically, I should have used
>> "SET TRANSACTION ISOLATION LEVEL ...".  This is the form from the SQL
>> standard, and is supported by Oracle, Microsoft SQL Server, and
>> Postgres.
>
> Hehe, except it isn't ;) In MSSQL the isolation level is a *session*
> setting, not a transaction setting. [...]

Oh yes, a more careful reading of
<http://msdn.microsoft.com/en-us/library/ms173763.aspx> shows you're
right here.

> I can't find the exact Oracle docu on the subject,
> and my testrig is down, but I believe it also maintains one setting per
> session, not per txn.[...]

A doc from Oracle on this is
<http://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_10005.htm>.
 This doc is clear that it's possible to have a transaction-scoped
thing for Oracle.

> [...]
> Which is why I outlined an exhaustive-ish list of what I can think of
> knowing the API ;) [...]

Thanks - and those comments will also be useful if I get a chance to
pursue this further.

> [...]
>
> "OMGWTFBBQ [...]
>
> I am still very much looking for something useful to come out of this thread.

Yep.  Cheers for the help setting out the direction and some of the
detail.  I'm glad you're not opposed to the feature in principle.  If
I do get a chance to work on this at all, I'll get in touch regarding
further API design and any implementation progress or difficulties.

I like the idea of a OMGWTFBBQ, though I admit I had to look up what it was.

  all the best, Stanley.



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