Forums

Web app suddendly very slow

I've made a website with Django and everything worked fine, but when I upgraded my account then my website stopped working. When i go to my website it keeps loading forever. Sometimes it seems that the website works normally (loads immediatly pages) but it's just for something like 5 sec, then again endless loading time. This is very strange, i've not modified my code, I've just upgraded my account. Reloading the web app takes a long time and i get the 'Your webapp took a long time to reload. It probably reloaded, but we were unable to check it.' message

Update: I see in the logs that the django view works because i see something printed out but the problem is when the server sends the response. Example:

def my_view(request):
    print("i can see this in the logs!")
    return HttpResponse("ok") # the view keeps loading but not 'ok' returned
Beloved premium user looma | 11 posts | Aug. 23, 2023, 4:58 p.m. | permalink

What do you see in the error and server logs? For the print calls, I'd suggest adding flush=True argument as well as redirection to stderr (file=sys.stderr), it's usually easier to read the output of the error log, than server log.

Staff pafk | 171 posts | PythonAnywhere staff | Aug. 24, 2023, 11:21 a.m. | permalink

error log:

2023-08-24 09:11:19,142: OSError: write error
2023-08-24 09:11:19,636: Not Found: /favicon.ico

server log:

2023-08-24 13:27:03 Thu Aug 24 13:27:03 2023 - received message 0 from emperor
2023-08-24 13:27:03 SIGINT/SIGTERM received...killing workers...
2023-08-24 13:27:04 worker 1 buried after 1 seconds
2023-08-24 13:27:04 worker 2 buried after 1 seconds
2023-08-24 13:27:04 goodbye to uWSGI.
2023-08-24 13:27:04 VACUUM: unix socket /var/sockets/looma.eu.pythonanywhere.com/socket removed.
2023-08-24 13:27:17 *** Starting uWSGI 2.0.20 (64bit) on [Thu Aug 24 11:27:07 2023] ***
2023-08-24 13:27:17 compiled with version: 9.4.0 on 22 July 2022 18:35:26
2023-08-24 13:27:17 os: Linux-5.15.0-1031-aws #35~20.04.1-Ubuntu SMP Sat Feb 11 16:19:06 UTC 2023
2023-08-24 13:27:17 nodename: blue-euweb2
2023-08-24 13:27:17 machine: x86_64
2023-08-24 13:27:17 clock source: unix
2023-08-24 13:27:17 pcre jit disabled
2023-08-24 13:27:17 detected number of CPU cores: 4
2023-08-24 13:27:17 current working directory: /home/looma
2023-08-24 13:27:17 detected binary path: /usr/local/bin/uwsgi
2023-08-24 13:27:17 *** dumping internal routing table ***
2023-08-24 13:27:17 [rule: 0] subject: path_info regexp: \.svgz$ action: addheader:Content-Encoding:gzip
2023-08-24 13:27:17 *** end of the internal routing table ***
2023-08-24 13:27:17 chdir() to /home/looma/
2023-08-24 13:27:17 your processes number limit is 256
2023-08-24 13:27:17 your memory page size is 4096 bytes
2023-08-24 13:27:17 detected max file descriptor number: 123456
2023-08-24 13:27:17 building mime-types dictionary from file /etc/mime.types...
2023-08-24 13:27:17 567 entry found
2023-08-24 13:27:17 lock engine: pthread robust mutexes
2023-08-24 13:27:17 thunder lock: disabled (you can enable it with --thunder-lock)
2023-08-24 13:27:17 uwsgi socket 0 bound to UNIX address /var/sockets/looma.eu.pythonanywhere.com/socket fd 3
2023-08-24 13:27:17 Python version: 3.10.5 (main, Jul 22 2022, 17:09:35) [GCC 9.4.0]
2023-08-24 13:27:17 PEP 405 virtualenv detected: /home/looma/.virtualenvs/mysite_venv
2023-08-24 13:27:17 Set PythonHome to /home/looma/.virtualenvs/mysite_venv
2023-08-24 13:27:17 *** Python threads support is disabled. You can enable it with --enable-threads ***
2023-08-24 13:27:17 Python main interpreter initialized at 0x560f1456fe50
2023-08-24 13:27:17 your server socket listen backlog is limited to 100 connections
2023-08-24 13:27:17 your mercy for graceful operations on workers is 60 seconds
2023-08-24 13:27:17 setting request body buffering size to 65536 bytes
2023-08-24 13:27:17 mapped 501384 bytes (489 KB) for 2 cores
2023-08-24 13:27:17 *** Operational MODE: preforking ***
2023-08-24 13:27:17 initialized 54 metrics
2023-08-24 13:27:17 couldn't import psycopg 'c' implementation: No module named 'psycopg_c'
2023-08-24 13:27:17 WSGI app 0 (mountpoint='') ready in 9 seconds on interpreter 0x560f1456fe50 pid: 1 (default app)
2023-08-24 13:27:17 *** uWSGI is running in multiple interpreter mode ***
2023-08-24 13:27:17 gracefully (RE)spawned uWSGI master process (pid: 1)
2023-08-24 13:27:17 spawned uWSGI worker 1 (pid: 2, cores: 1)
2023-08-24 13:27:17 spawned 2 offload threads for uWSGI worker 1
2023-08-24 13:27:17 spawned uWSGI worker 2 (pid: 5, cores: 1)
2023-08-24 13:27:17 metrics collector thread started
2023-08-24 13:27:17 spawned 2 offload threads for uWSGI worker 2
2023-08-24 13:27:22 
2023-08-24 13:27:22 RENDERING INDEX
2023-08-24 13:27:22 
2023-08-24 13:27:37

2023-08-24 13:32:19 Thu Aug 24 13:32:18 2023 - *** HARAKIRI ON WORKER 1 (pid: 2, try: 1) ***
2023-08-24 13:32:19 Thu Aug 24 13:32:18 2023 - HARAKIRI !!! worker 1 status !!!
2023-08-24 13:32:19 Thu Aug 24 13:32:18 2023 - HARAKIRI [core 0] 10.0.0.162 - GET / since 1692876437
2023-08-24 13:32:19 Thu Aug 24 13:32:18 2023 - HARAKIRI !!! end of worker 1 status !!!
2023-08-24 13:32:19 DAMN ! worker 1 (pid: 2) died, killed by signal 9 :( trying respawn ...
2023-08-24 13:32:19 Respawned uWSGI worker 1 (new pid: 10)
2023-08-24 13:32:19 spawned 2 offload threads for uWSGI worker 1
2023-08-24 13:32:35 Thu Aug 24 13:32:34 2023 - *** HARAKIRI ON WORKER 2 (pid: 5, try: 1) ***
2023-08-24 13:32:35 Thu Aug 24 13:32:34 2023 - HARAKIRI !!! worker 2 status !!!
2023-08-24 13:32:35 Thu Aug 24 13:32:34 2023 - HARAKIRI [core 0] 10.0.0.162 - GET / since 1692876453
2023-08-24 13:32:35 Thu Aug 24 13:32:34 2023 - HARAKIRI !!! end of worker 2 status !!!
2023-08-24 13:32:35 DAMN ! worker 2 (pid: 5) died, killed by signal 9 :( trying respawn ...
2023-08-24 13:32:35 Respawned uWSGI worker 2 (new pid: 13)
2023-08-24 13:32:35 spawned 2 offload threads for uWSGI worker 2

The error about psycopg (couldn't import psycopg 'c' implementation: No module named 'psycopg_c') is "normal", i have it also in local and it doesn't stop the server from running. Thanks for your time

Beloved premium user looma | 11 posts | Aug. 24, 2023, 11:35 a.m. | permalink

I'm guessing that the view code that you put into your first message in this thread is an example rather than the actual code that's there; if you put prints in between different lines in the code, is there a particular one that is blocking? It's a good idea to put the flush=True keyword in there to make sure that the output is written to the log file.

Staff giles | 225 posts | PythonAnywhere staff | Aug. 24, 2023, 5:09 p.m. | permalink

I found the problem, it's the db, for some reason is very very slow. Switching back to sqlite and everything worked again. I don't even know how i didn't notice that before, probably i changed database just after upgrading the account and forgot about it, feeling kinda stupid but happy to have at least found out what the problem was.

Beloved premium user looma | 11 posts | Aug. 24, 2023, 6:15 p.m. | permalink

Thanks for letting us know!

Staff pafk | 171 posts | PythonAnywhere staff | Aug. 25, 2023, 5:31 p.m. | permalink