As much as I agree with your decision, it just makes me sad.   I know lots
of people that learned scala for "actors are the way of the future".... I
think we need to push harder.  Hopefully all major projects migrating off
actors will give EPFL a wake up call?

- Josh

On Tue, Sep 29, 2009 at 1:41 PM, David Pollak <feeder.of.the.be...@gmail.com
> wrote:

>
>
> On Tue, Sep 29, 2009 at 2:35 AM, Stuart Roebuck 
> <stuart.roeb...@gmail.com>wrote:
>
>>
>> Apologies if I've missed something obvious but my web search hasn't
>> turned anything up...
>>
>> What are the Scala Actors instability issues? I'm in the process of
>> doing some major Scala development work and this comment raises
>> concerns that I'd like to understand.
>>
>
> The issues (with the Scala Actors in general and Lift's use of them) are:
>
>    - Scala Actors use a custom version of Doug Leah's Fork/Join library.
>     This was necessary for JDK 1.4 support.  With JDK 1.5, the
>    java.util.concurrent stuff should have been used.  I was led to understand
>    that this change was made in Scala 2.7.5, but it was not and even the Scala
>    2.8 stuff still contains fork-join.  The FJ library has a memory retention
>    issue where it trades memory for non-locking performance and, with many
>    threads in a thread-pool, this leads to out of memory issues.
>    - The Scala Actor code is very brittle.  See
>    http://erikengbrecht.blogspot.com/2009/01/refactoring-scala-actors.html 
> The code has not been materially refactored, which means that even in 2.8,
>    there will be significant potential problems with the Actors.  Those
>    potential problems have manifest themselves as real problems in 2.7.x.  I
>    have spent in aggregate nearly 3 weeks of my time since November 2008
>    working around the defects in the Actor library.  It's easier to have our
>    own Actors (the current Actor library is about 2 days of work on my part 
> and
>    the refactoring of Lift to work with the existing Actor library is another 
> 2
>    days of work.)
>    - EPFL has been generally slow to respond to bug reports.  I am very
>    frustrated and quite frankly tired of having to cajole EPFL into responding
>    to defects in one of the premier Scala libraries.
>
> I would strongly suggest that you look at Akka.  It's got a better view and
> implementation of Actors than does the standard Scala distribution. Akka
> includes support for distributed actors, etc.
>
> Hope this helps.
>
>
>>
>> Best,
>>
>> Stuart
>>
>> On Sep 29, 3:30 am, David Pollak <feeder.of.the.be...@gmail.com>
>> wrote:
>> > Folks,
>> >
>> > Given the continued instability of Scala Actors, I've decided to remove
>> them
>> > from Lift.
>> >
>> > Specifically, I'm migrating CometActors to sit on top of Lift's Actors.
>> > But, you'll also be able to use Akka Actors to power Lift's CometActors.
>> > Specifically, I'm working with Jonas to make sure that we share a common
>> > interface to Actors.
>> >
>> > I've gotten Lift nearly completely migrated over to Lift's Actors on the
>> > dpp_wip_actorize branch.  Seehttp://
>> github.com/dpp/liftweb/tree/dpp_wip_actorize
>> >
>> > There will be some breaking changes to your applications.  Specifically:
>> >
>> >    - Box will be moved to a new package, net.liftweb.base (this is where
>> the
>> >    interface for Actors will live as well)
>> >    - If you make any assumptions about your CometActors being Scala
>> Actors
>> >    (e.g., using linking), you will have to rewrite this code
>> >    - Some methods in Lift that currently take Scala Actors as parameters
>> >    will take Lift Actors (e.g., ActorPing)
>> >
>> > There will be a parallel Maven repository with the new Lift Actor stuff
>> in
>> > it so you will be able to build you apps against the new code before the
>> > official switch-over.
>> >
>> > Milestone 6 (which should be out next week) will be based on the
>> existing
>> > Actor model.  After we get feedback from the community about the new
>> Actor
>> > stuff, we will switch -SNAPSHOT over to the new Actor stuff.
>> >
>> > Questions, thoughts, or comments?
>> >
>> > Thanks,
>> >
>> > David
>> >
>> > --
>> > Lift, the simply functional web frameworkhttp://liftweb.net
>> > Beginning Scalahttp://www.apress.com/book/view/1430219890
>> > Follow me:http://twitter.com/dpp
>> > Surf the harmonics
>>
>>
>>
>
>
> --
> Lift, the simply functional web framework http://liftweb.net
> Beginning Scala http://www.apress.com/book/view/1430219890
>
> Follow me: http://twitter.com/dpp
> Surf the harmonics
>
> >
>

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups 
"Lift" group.
To post to this group, send email to liftweb@googlegroups.com
To unsubscribe from this group, send email to 
liftweb+unsubscr...@googlegroups.com
For more options, visit this group at 
http://groups.google.com/group/liftweb?hl=en
-~----------~----~----~----~------~----~------~--~---

Reply via email to