BlockingPool must fit thread_count (#894)

queue_size must be greater than or equal to thread_count, or else the main thread can hang trying to acquire a lock to write sentinel values to the queue during teardown.
2019-04-26 11:57:11 -06:00
parent dd72153a71
commit fda9d3429c
1 changed files with 3 additions and 1 deletions
@@ -347,7 +347,9 @@ def parallel_bulk(
    class BlockingPool(ThreadPool):
        def _setup_queues(self):
            super(BlockingPool, self)._setup_queues()
-            self._inqueue = Queue(queue_size)
+            # The queue must be at least the size of the number of threads to 
+            # prevent hanging when inserting sentinel values during teardown.
+            self._inqueue = Queue(max(queue_size, thread_count))
            self._quick_put = self._inqueue.put

    pool = BlockingPool(thread_count)