> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of David
> Jencks
> Sent: Wednesday, June 27, 2001 4:12 PM
> To: [EMAIL PROTECTED]
> Subject: RE: [JBoss-dev] CVS update:
> jboss/src/main/org/jboss/ejb/plugins/jaws/jdbc JDBCCommand.java
>
>
> Hi,
> Thanks, someone finally looked at the code more.
>
> Yes, Jaws can't set the transaction isolation, the DataSource is just a
> facade for getting a Connection(handle) to a XA/ManagedConnection that
> actually talks to the db and has the transaction associated with it by the
> XAResource. By the time Jaws gets the connection , the transaction has
> already been associated. (the xa wrappers do this by finding the
> connection
> that the transactin was actually started on, and using it). So, I think
> the transaction-associating code ought to be able to set transaction
> isolation too, at the same time. There are 2 cases I think will work:
>
> 1. xa wrappers, a jdbc 1 connection can only have one transaction at a
> time, no suspend/resume. So you set the isolation when you create the
> transaction initially, and ignore it thereafter ( you should always be
> setting it to the same isolation anyway).
>
> 2. This will also work for the jca firebird driver I am working on for
> essentially the same reason.
>
> However I don't know what would happen with someone elses true xa driver.
> Since you can only have one transaction associated with an xa
> resource at a
> time, I would expect it to be possible to set the isolation before
> associating the transaction... but I don't know that there is an interface
> for doing this.
>
> Basically the problem is that the isolation is a property of the
> transaction, but java doesn't put it there.
>
> I'm rapidly starting to think that this may be too much trouble.
>
My whole point from the beginning.
> Bill, I think you were the main motivation for all this dynamic isolation
> configuring. Can you eliminate your need for serializable transactions on
> a few tables by explicitly keeping several versions around and finding a
> way to get the correct version?
>
David, I have no requirement for dynamic isolation configuration. Dain, had
modified JAWS to enable dynamic isolation configuration and I was trying to
convince him and Marc(not very well btw) that this was a bad idea. I was
trying to make the point that you could get different isolation for
different bean types by attaching different pools to those beans. You're
totally right that without true XA and 2pc, using 2 different pools is
probably a bad idea and should be avoided at all costs.
Sorry for all the confusion I generated, but at least we're all in agreement
now?
Bill
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