On Thu, Sep 17, 2009 at 11:04 AM, Mark Volkmann <r.mark.volkm...@gmail.com>wrote:
> On Thu, Sep 17, 2009 at 9:57 AM, Chouser <chou...@gmail.com> wrote: > > > > On Thu, Sep 17, 2009 at 12:28 AM, Krukow <karl.kru...@gmail.com> wrote: > >> > >> Final question. The docs say that 'ensure' permits more concurrency > >> than promoting the ref to a write. Is there a quick/simple way of > >> explaining how? (Or do I need to go to the source :-) > > > > If you have multiple transactions ensuring the same var but > > no transactions changing it, all those transactions can > > proceed simultaneously. If they all did dummy writes > > instead of ensure, they could only proceed in order. > > Ah ... I think I misunderstood an important part of the question. I > wasn't assuming that all the concurrent transactions were going to use > ensure or a dummy write on the same Ref. So the key is that multiple > transactions can successfully ensure the same Ref, but multiple > transactions cannot successfully write the same Ref. Not with ref-set! or alter!, but maybe with commute identity? --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
