Ok, I have a 1 and 2 :) So is it pessimistic or optimistic? So encounter time ensure or commit time ensure?
On Sep 14, 9:36 pm, Stuart Halloway <stuart.hallo...@gmail.com> wrote: > Actually, the second one is basically it. (Except that I don't know the > Oracle reference, so can't speak to that.) > > Stu > > > The first one is correct. > > > On Tue, Sep 14, 2010 at 3:22 PM, peter veentjer <alarmnum...@gmail.com> > > wrote: > > I have got a question about the Clojure ensure and how it actually > > works and the documentation doesn't provide enough information. > > > I see a few different solutions: > > > 1) An optimistic approach: Once a ref is 'ensured' it is included in > > the conflict detection set. This means that the approach is still > > completely optimistic because 2 concurrent transactions that have the > > same ensured ref, one of them is going to fail when the transaction > > wants to commit. This is a commit time ensure. > > > 2) The other approach is a more pessimistic approach where a ref can > > be protected against writes made by other transaction as soon as it is > > ensured. It still allows reads to happen, but a write/ensure is going > > to fail. It could be compared to a oracle 'select.. for update'. This > > is an encounter time ensure. > > > -- > > You received this message because you are subscribed to the Google > > Groups "Clojure" group. > > To post to this group, send email to clojure@googlegroups.com > > Note that posts from new members are moderated - please be patient with > > your first post. > > To unsubscribe from this group, send email to > > clojure+unsubscr...@googlegroups.com > > For more options, visit this group at > >http://groups.google.com/group/clojure?hl=en -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
