[GitHub] storm pull request #1764: STORM-2190: reduce contention between submission a...

[revans2 <gi...@git.apache.org>]

Github user revans2 commented on a diff in the pull request:

    https://github.com/apache/storm/pull/1764#discussion_r90538639
  
    --- Diff: storm-core/src/clj/org/apache/storm/daemon/nimbus.clj ---
    @@ -1008,23 +1008,24 @@
           (reset! (:id->worker-resources nimbus) {}))
         ;; tasks figure out what tasks to talk to by looking at topology at runtime
         ;; only log/set when there's been a change to the assignment
    -    (doseq [[topology-id assignment] new-assignments
    -            :let [existing-assignment (get existing-assignments topology-id)
    -                  topology-details (.getById topologies topology-id)]]
    -      (if (= existing-assignment assignment)
    -        (log-debug "Assignment for " topology-id " hasn't changed")
    -        (do
    -          (log-message "Setting new assignment for topology id " topology-id ": " (pr-str assignment))
    -          (.setAssignment storm-cluster-state topology-id (thriftify-assignment assignment))
    -          )))
    -    (->> new-assignments
    -          (map (fn [[topology-id assignment]]
    -            (let [existing-assignment (get existing-assignments topology-id)]
    -              [topology-id (map to-worker-slot (newly-added-slots existing-assignment assignment))]
    -              )))
    -          (into {})
    -          (.assignSlots inimbus topologies)))
    -    (log-message "not a leader, skipping assignments")))
    +    (locking (:sched-lock nimbus)
    --- End diff --
    
    @jerrypeng You are correct that this could happen.  I don't really think it will be that likely to happen in practice but I'll think about it and see if we can fix it.


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