[Z3-sqlos] RFC: Transaction simplification branch

[Stuart Bishop]

Brian Sutherland wrote:
> On Fri, Dec 09, 2005 at 12:50:45PM +0700, Stuart Bishop wrote:
> 
>>>>|  * Why do we expire objects in a successful transaction? I can't think
>>>>|    of a reason why we need to.
>>
>>You need to expire objects after a successful transaction so you can see
>>database changes made by other processes or threads. This is particularly
>>important for Zope where you have a number of handler threads and possibly
>>multiple application servers in a ZEO environment.
> 
> Great, I reverted my patch and added a big warning because I don't want
> to imagine writing a test for that.
> 
> But there is another issue with what you bring up, so far we only expire
> objects that have been changed during the transaction. By what you say,
> we should be expiring _every_ object on our thread.

Yes - in our app we blow away the thread's entire cache at the transaction
start (but our publisher and sqlos layers have been customised/lobotomised
enough to not be generally useful to others).

        name = getUtility(IConnectionName).name
        key = (thread.get_ident(), name)
        cache = sqlos.connection.connCache
        if cache.has_key(key):
            del cache[key]

-- 
Stuart Bishop <stuart.bishop at canonical.com>   http://www.canonical.com/
Canonical Ltd.                                http://www.ubuntu.com/
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