[Zope] Re: database conflicts and the _p_oid missing attribute bug
Dennis Allison
allison at shasta.stanford.edu
Fri Jan 23 12:10:47 EST 2004
Jeremy -- when will 3.3 be ready for prime time? -d
On Fri, 23 Jan 2004, Jeremy Hylton wrote:
> On Fri, 23 Jan 2004 11:54:38 -0500
> Shane Landrum <srl at boston.com> wrote:
> > Where can I read about writing my own conflict
> > resolution?
> > What risks are there with this approach, and how do I
> > minimize them?
>
> The subject isn't well-documented. I hope we'll improve
> the documentation for 3.3, and this is one of the issues
> the bears explaning.
>
> In the interim, here are two possibilities.
>
> Jim's wiki has a page that describes the basic API. It's
> all correct and has some simple example code.
> http://www.zope.org/Members/jim/ZODB/ApplicationLevelConflictResolution
>
> I think it doesn't address cross-object consistency issues.
> If you have two (or more) objects and there is an
> invariant that spans those two objects, you need to be very
> careful about maintaining that invariant in the face of
> conflict resolution. BTrees have to deal with that.
>
> I also wrote a technical note in my weblog about avoiding
> contention. It discusses several approaches, but it's just
> a sketch of some ideas.
> http://www.python.org/~jeremy/weblog/031031c.html
>
> If these don't answer your questions or provoke new
> questions, feel free to ask. It will help us understand
> what new documentation is needed.
>
> Jeremy
>
--
Dennis Allison * Computer Systems Laboratory * Gates 227
* Stanford University * Stanford CA 94305
* (650) 723-9213 * (650) 723-0033 fax
* allison at shasta.stanford.edu
* allison at sumeru.stanford.edu
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