当给定大量线程时，Python多处理线程永远不会连接

Question

我不相信这是this的重复，因为他的问题似乎是由使用multiprocessing.pool引起的，而我没有这么做。在

该计划：

import multiprocessing
import time

def task_a(procrange,result):
    "Naively identify prime numbers in an iterator of integers. Procrange may not contain negative numbers, 0, or 1. Result should be a multiprocessing.queue."

    for i in procrange: #For every number in our given iterator...
        for t in range (2,(i//2)+1): #Take every number up to half of it...
            if (i % t == 0): #And see if that number goes evenly into it.
                break   #If it does, it ain't prime.
        else:
            #print(i)
            result.put(i) #If the loop never broke, it's prime.




if __name__ == '__main__':
    #We seem to get the best times with 4 processes, which makes some sense since my machine has 4 cores (apparently hyperthreading doesn't do shit)
    #Time taken more or less halves for every process up to 4, then very slowly climbs back up again as overhead eclipses the benifit from concurrency
    processcount=4
    procs=[]
    #Will search up to this number.
    searchto=11000
    step=searchto//processcount
    results=multiprocessing.Queue(searchto)
    for t in range(processcount):
        procrange=range(step * t, step * (t+1) )
        print("Process",t,"will search from",step*t,"to",step*(t+1))
        procs.append(
                     multiprocessing.Process(target=task_a, name="Thread "+str(t),args=(procrange,results))
                     )
    starttime=time.time()
    for theproc in procs:
        theproc.start()
    print("Processing has begun.")

    for theproc in procs:
        theproc.join()
        print(theproc.name,"has terminated and joined.")
    print("Processing finished!")
    timetook=time.time()-starttime

    print("Compiling results...")

    resultlist=[]
    try:
        while True:
            resultlist.append(results.get(False))
    except multiprocessing.queues.Empty:
        pass

    print(resultlist)
    print("Took",timetook,"seconds to find",len(resultlist),"primes from 0 to",searchto,"with",processcount,"concurrent executions.")

。。。工作完美，结果是：

^{pr2}$

然而，如果search_to增加500。。。在

Processing has begun.
Thread 0 has terminated and joined.
Thread 1 has terminated and joined.
Thread 2 has terminated and joined.

。。。剩下的就是沉默。进程黑客显示Python线程每个消耗12%的CPU，一个接一个地消耗掉。。。而不是终止。它们一直挂着直到我手动终止它们。在

为什么？在

**显然，无论是上帝还是圭多都有一种残酷的幽默感。在

Answer 1

似乎result.put(i)中有一个问题，因为当我提交它时，脚本开始运行良好。所以我建议您不要使用来保存结果multiprocessing.Queue。相反，您可以使用数据库：MySQL、MongoDB等。注意：您不能使用SQLite，因为在SQLite中，在任何时刻（从docs）只有一个进程可以对数据库进行更改。在