芹菜3.1.19为每个工作人员创建太多线程，导致服务器超载，CPU 100%无法创建更多线程

Question

用例:使用Django框架(版本1.6 )中的芹菜来调度本质上写到数据库的任务。我只有一个自定义队列，芹菜调度程序把任务放在上面。创建了一个侦听此队列中并发性为8的芹菜工人。

问题:8个工作人员中的每个人都会继续创建从未被回收的线程(我猜)。这导致线程太多(我见过计数上升到20k线程)。在4-5小时的时间内，线程数触及10k！

我看到了错误:无法启动新线程。

Python对正在启动新线程的人的跟踪给了我以下信息:调用django保存会创建一个新线程。“adgroup”这里是django模型对象

[2015-12-03 18:40:17,133: WARNING/Worker-3] adgroup.save(update_fields=['bids_today', 'impressions_today', 'spent_today', 'last_metric_update_time'])
[2015-12-03 18:40:17,887: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/django/db/models/base.py", line 545, in save
[2015-12-03 18:40:17,887: WARNING/Worker-3] force_update=force_update, update_fields=update_fields)
[2015-12-03 18:40:18,715: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/django/db/models/base.py", line 582, in save_base
[2015-12-03 18:40:18,716: WARNING/Worker-3] update_fields=update_fields, raw=raw, using=using)
[2015-12-03 18:40:18,716: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/django/dispatch/dispatcher.py", line 185, in send
[2015-12-03 18:40:18,716: WARNING/Worker-3] response = receiver(signal=self, sender=sender, **named)
[2015-12-03 18:40:19,300: INFO/MainProcess] Task ExtendTV.celery_tasks.stats_collector.collectAdGroupMetricsTask[2ae52b3d-77b9-46d3-93ac-d7fad9b96382] succeeded in 26.486441362s: None
[2015-12-03 18:40:19,395: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/haystack/signals.py", line 48, in handle_save
[2015-12-03 18:40:19,593: WARNING/Worker-3] index.update_object(instance, using=using)
[2015-12-03 18:40:19,593: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/haystack/indexes.py", line 274, in update_object
[2015-12-03 18:40:19,593: WARNING/Worker-3] backend.update(self, [instance])
[2015-12-03 18:40:19,593: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/haystack/backends/whoosh_backend.py", line 208, in update
[2015-12-03 18:40:20,515: WARNING/Worker-3] writer.commit()
[2015-12-03 18:40:20,516: WARNING/Worker-3] File "/home/ec2-user/venv/local/lib/python2.7/dist-packages/whoosh/writing.py", line 1043, in commit
[2015-12-03 18:40:21,318: WARNING/Worker-3] self.start()
[2015-12-03 18:40:21,642: WARNING/Worker-3] File "/usr/lib64/python2.7/threading.py", line 748, in start
[2015-12-03 18:40:22,340: WARNING/Worker-3] _start_new_thread(self.__bootstrap, ())
[2015-12-03 18:40:22,340: WARNING/Worker-3] error: can't start new thread

Misc信息:从图片中可以看到，内存在正常范围内。这个“线程问题”并不存在于芹菜的前一个版本3.0.x中。然而，在这里，内存变得相当高。

我用芹菜命令来创造一个工人：

celery -A ProjectName worker -l DEBUG -Q ExampleQueueName

我用的芹菜布景：

CELERY_DEFAULT_QUEUE = 'default'
CELERY_DEFAULT_EXCHANGE_TYPE = 'direct'
CELERY_DEFAULT_ROUTING_KEY = 'default'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_ACCEPT_CONTENT = ['json']
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_TASK_RESULT_EXPIRES=60*60*24
CELERYD_PREFETCH_MULTIPLIER = 128

其他相关设置:使用rabbitmq 3.5.4作为消息代理

最新情况：

def collectAdGroupMetricsTask(*args, **kwargs):
    try:
        adgroup = AdGroup.objects.get(id=kwargs.get("adgroupID"))
        collectAdGroupMetrics(adgroup)
    except Exception as e:
        logger.error("Could not retreive AdGroup for collectAdGroupMetrics. " + str(e))
    return

def collectAdGroupMetrics(adgroup, currDate=None):
    Value1=function1_making_another_db_call()
    Value2=function2_making_another_db_call()
    adgroup.fieldname1 = Value1
    adgroup.fieldname2 = Value2    
    adgroup.save(update_fields=['fieldname1', 'fieldname2'])

工作进程有很多线程的例子。

Answer 1

whoosh ( package)出现了一个问题，它试图获得一个写锁，并一直在等待，导致创建了这么多threads.Hence，从django中安装的应用程序列表中删除了whoosh。同时，在芹菜中使用maxtasksperchild配置，以防止内存持续增长。

Answer 2

• 首先，在pythonic虚拟环境中安装了包gevent。
• Next对运行芹菜的命令做了一些更改
• 最后，我附加了参数--pool gevent。默认情况下，芹菜使用池‘pre叉’，这应该有一些bug。
• 选择后，，，，芹菜，的进程数降低到子进程数(并发)。