Taking a quick look at this, I *think* the problem crops up in your tasks
being a lazy sequence.
Modify this
(def tasks (ref (range 1 10000000)))
to this
(def tasks (ref (doall (range 1 10000000))))
Running that with your large endpoint was taking a lot of time, so I'd
suggest running it with 1e5 as that will finish much quicker.
On Tuesday, August 23, 2016 at 8:22:00 AM UTC-4, Sergei Koledov wrote:
>
> Hello,
>
> I had a problem when I run the following code:
>
> (defn get-task [tasks]
> (dosync
> (let [task (first @tasks)]
> (alter tasks rest)
> task)))
>
> (defn worker [& {:keys [tasks]}]
> (agent {:tasks tasks}))
>
> (defn worker-loop [{:keys [tasks] :as state}]
> (loop [last-task nil]
> (if-let [task (get-task tasks)]
> (recur task)
> (locking :out (println "Last task: " last-task))))
> state)
>
> (defn create-workers [count & options]
> (->> (range 0 count)
> (map (fn [_] (apply worker options)))
> (into [])))
>
> (defn start-workers [workers]
> (doseq [worker workers] (send-off worker worker-loop)))
>
> (def tasks (ref (range 1 10000000)))
>
> (def workers (create-workers 100 :tasks tasks))
>
> (start-workers workers)
> (apply await workers)
>
> Description: I have several agents (100 in my case). Each agent running in
> a separate thread. All agents share the one ref with the collection of
> tasks (range of longs in my case). Each agent get tasks from the collection
> (in transaction) one by one until the collection becomes empty and then
> prints the last task which it handle. However, when I run this code it
> looks like the collection of tasks suddenly becomes empty and workers
> handle only portion of all tasks (average 25-40% of all number).
>
> This code behave as I expected, when I create only one agent or use
> explicit locking in get-task function:
>
> (defn get-task [tasks]
> (locking :lock
> (dosync
> (let [task (first @tasks)]
> (alter tasks rest)
> task))))
>
> I run this code on the Clojure 1.8.0
> java version "1.8.0_91"
> Java(TM) SE Runtime Environment (build 1.8.0_91-b14)
> Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)
>
> Can anyone tell me, what am I doing wrong, or it really looks like a bug
> in the clojure STM?
> I already asked this question on stackoverflow.com (
> http://stackoverflow.com/questions/39054911/strange-behavior-of-clojure-ref),
> but so far nobody has been able to help me.
>
> P.S. Sorry for my english skill.
>
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