Setting of MaxRequestWorker (MaxClients) has connections to other MPM settings,
so must see those as well.
Also usually would be no need to set MaxConnectionsPerChild either if
everything else is setup correctly when using mod_wsgi daemon mode.
Since using mod_wsgi daemon mode there isn't a need to recycle Apache child
worker processes, nor restrict the Apache child workers so they are single
threaded
Rather than cut and paste piece meal parts of your configuration, I need to see
the whole mod_wsgi parts of the configuration, plus all the Apache MPM settings.
So need to see all the settings for the following, depending on whether using
worker or event MPM. The preferred these days is the "event" MPM.
<IfModule mpm_worker_module>
StartServers 3
MinSpareThreads 75
MaxSpareThreads 250
ThreadsPerChild 25
MaxRequestWorkers 400
MaxConnectionsPerChild 0
</IfModule>
<IfModule mpm_event_module>
StartServers 3
MinSpareThreads 75
MaxSpareThreads 250
ThreadsPerChild 25
MaxRequestWorkers 400
MaxConnectionsPerChild 0
</IfModule>
Also need to see what you have for:
WSGIDaemonProcess
WSGIProcessGroup
WSGIScriptAlias
WSGIRestrictEmbedded
ThreadStackSize
But I need to see where you stick the WSGI directives in relation to other
stuff you have in the VirtualHost to check whether the location is correct and
thus whether applied.
Graham
> On 13 Aug 2020, at 3:57 am, Paul Royik <[email protected]> wrote:
>
> So, I watched the video, changed the architecture using Celery.
> Now requests are processed very quickly.
>
> Here is my configuration.
> StartServers 1
> ServerLimit 5
> MaxRequestWorkers 125
> MaxConnectionsPerChild 10000
>
> WSGIDaemonProcess django_app processes=15 threads=5
>
>
> As I understand this allows 75 concurrent requests in mod_wsgi and 125
> requests in apache.
> Is there any reason to make number of concurrent requests in apache higher
> than in mod_wsgi, i.e. 125 vs. 75? Possibly, set it 75 in both cases? I don't
> understand this point.
>
> The second question. Things become really faster, but from time to time I got
> 502 error. It appears that apache is killed, because I need to start the
> server manually.
> What are the possible reasons for this? RAM, too many requests? Can you give
> me some suggestions?
>
> Thank you.
>
> On Tuesday, August 11, 2020 at 12:09:19 PM UTC+3, Paul Royik wrote:
> I'll watch. Thank you!
>
> On Tuesday, August 11, 2020 at 11:39:27 AM UTC+3, Graham Dumpleton wrote:
> Did you watch the videos? That is covered in some of them.
>
>> On 11 Aug 2020, at 5:57 pm, Paul Royik <[email protected] <>> wrote:
>>
>> Can you at least tell me how apache settings coordinate with mod_wsgi
>> settings?
>>
>> I set number of threads, processes in Apache and in mod_wsgi. How do they
>> work together?
>>
>> In mod_wsgi processes=5 threads=12. Does it mean 60 concurrent requests?
>>
>> On Tuesday, August 11, 2020 at 10:31:56 AM UTC+3, Graham Dumpleton wrote:
>> The problem was you had other odd requirements like having non thread safe
>> code.
>>
>> All I can do is suggest you watch these videos.
>>
>> https://www.youtube.com/watch?v=CPz0s1CQsTE&t=4s
>> <https://www.youtube.com/watch?v=CPz0s1CQsTE&t=4s>
>> https://www.youtube.com/watch?v=SGleKfigMsk&t=2s
>> <https://www.youtube.com/watch?v=SGleKfigMsk&t=2s>
>> https://www.youtube.com/watch?v=k6Erh7oHvns&t=1s
>> <https://www.youtube.com/watch?v=k6Erh7oHvns&t=1s>
>>
>> There is no simple answer as one needs to know how your application works
>> and have access to performance metrics from an APM service in order to tune
>> the server.
>>
>> Graham
>>
>>> On 11 Aug 2020, at 5:27 pm, Paul Royik <distan...@ <>gmail.com
>>> <http://gmail.com/>> wrote:
>>>
>>> One more question.
>>>
>>> What is a good configuration if I have 500 concurrent requests and there
>>> are no long-running tasks?
>>>
>>> On Tuesday, August 11, 2020 at 9:52:39 AM UTC+3, Paul Royik wrote:
>>> Thank you for your help.
>>>
>>> On Tuesday, August 11, 2020 at 8:30:27 AM UTC+3, Graham Dumpleton wrote:
>>> If it is a minor quick running script that does something simple it should
>>> be okay. It is just having long running processes would be more concerned
>>> about.
>>>
>>>> On 11 Aug 2020, at 3:18 pm, Paul Royik <distan...@ <>gmail.com
>>>> <http://gmail.com/>> wrote:
>>>>
>>>> You are absolutely correct. Need to change the architecture.
>>>> One more question. I also use subprocess.check_output from django. Is it
>>>> also bad idea? I'm trying to run a script (non-python) and get it output.
>>>>
>>>> On Tuesday, August 11, 2020 at 1:55:51 AM UTC+3, Graham Dumpleton wrote:
>>>> Personally I would be concerned about the architecture you are using if
>>>> you have long running tasks like you describe. It is not usually a good
>>>> idea to use 'multiprocessing.Process' to create sub processes directly
>>>> from a web server process to perform work. A better architecture would be
>>>> to off load the work into a queue using something like Celery and have the
>>>> separate job processing system pull the jobs from the queue and process
>>>> them. You would also be better off to model the interaction from the front
>>>> end as queueing the job and immediately responding with an acknowledgement
>>>> to say is queued. The front end can then start polling periodically to see
>>>> if the job has finished, and when it has it would get the response back.
>>>> The front end can then display the data or save it locally as needed.
>>>>
>>>> This model avoids the problem of requests being parked doing nothing for a
>>>> long time, which with your server configuration is going to be hugely
>>>> expensive on memory and not scale very well because of limitations of
>>>> using WSGI process/threading model. You might even consider not using a
>>>> WSGI application at all. Instead, use an async web application paired with
>>>> Celery for execution of the jobs. Using an async web application means you
>>>> can handle as many parked requests as you want and they can quite happily
>>>> sit there waiting for Celery to finish the job and don't need to use
>>>> polling. Only thing am not sure about in that is what async clients there
>>>> are for Celery.
>>>>
>>>> Graham
>>>>
>>>>> On 10 Aug 2020, at 9:09 pm, Paul Royik <distan...@ <>gmail.com
>>>>> <http://gmail.com/>> wrote:
>>>>>
>>>>> My django app makes heavy calculations which can be infinite.
>>>>> That's why, when user enters the site, i.e. makes a request, heavy
>>>>> calculations are wrapped into multiprocessing.Process which runs at most
>>>>> 7 seconds.
>>>>> I can't use threads, because third-party packages are not thread-safe.
>>>>>
>>>>> So, I have around 30 concurrent requests per second. If each request can
>>>>> take up to 7 seconds, then it is 30*7=210 concurrent requests in the
>>>>> worst case.
>>>>> Each of these concurrent requests opens multiprocessing.Process, which
>>>>> gives (I guess) 210*2=420 (close to 500) concurrent requests in the worst
>>>>> case.
>>>>> That' how I got 500 requests. Possibly, my calculations are incorrect.
>>>>>
>>>>> Average page load time (average response times) is 10 seconds.
>>>>>
>>>>> I use MPM worker.
>>>>>
>>>>> I set WSGIProcessGroup
>>>>>
>>>>> StartServers 100
>>>>> ServerLimit 500
>>>>>
>>>>> ThreadsPerChild 1
>>>>> ThreadLimit 1
>>>>>
>>>>> MaxRequestWorkers 500
>>>>> MaxConnectionsPerChild 10000
>>>>>
>>>>> WSGIApplicationGroup %{GLOBAL}
>>>>> WSGIDaemonProcess django_app processes=75 threads=1 python-path='...'
>>>>> maximum-requests=10000 request-timeout=20
>>>>> WSGIProcessGroup django_app
>>>>> WSGIRestrictEmbedded On
>>>>> WSGILazyInitialization On
>>>>>
>>>>>
>>>>> On Monday, August 10, 2020 at 1:12:30 PM UTC+3, Graham Dumpleton wrote:
>>>>> What sort of application are you running?
>>>>>
>>>>> What is your average response times?
>>>>>
>>>>> Do you have long running requests, if yes, how long?
>>>>>
>>>>> What Apache MPM are you actually using?
>>>>>
>>>>> My initial impression is that is a quite poor configuration which is only
>>>>> going to chew up huge amounts of memory for no good reason, but I don't
>>>>> know your application requirements.
>>>>>
>>>>> Also, are you even setting WSGIProcessGroup? If it isn't set it makes
>>>>> the whole daemon process configuration moot as it isn't even being used.
>>>>>
>>>>>> On 10 Aug 2020, at 7:24 pm, Paul Royik <distan...@ <>gmail.com
>>>>>> <http://gmail.com/>> wrote:
>>>>>>
>>>>>> StartServers 50
>>>>>> ServerLimit 200
>>>>>>
>>>>>> ThreadsPerChild 1
>>>>>> ThreadLimit 1
>>>>>>
>>>>>> MaxRequestWorkers 200
>>>>>> MaxConnectionsPerChild 10000
>>>>>>
>>>>>> WSGIApplicationGroup %{GLOBAL}
>>>>>> WSGIDaemonProcess process processes=75 threads=1
>>>>>>
>>>>>>
>>>>>> Is it enough? Or can it handle only 75 concurrent requests? I don't know
>>>>>> how to synchronize apache and mod_wsgi settings.
>>>>>>
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>>>>>
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