thanks for your response.
to clarify, my app doesn't spawn any threads (that i know of at least). the only recent change i can think of is that i'm using a pip package called natty which calls into java but i don't think it's spawning threads.
as to logs: my error log hasn't seen anything new in hours but my server log is spewing the following every 2 minutes or so:
2017-08-21 18:02:33 *** Starting uWSGI 2.0.14 (64bit) on [Mon Aug 21 18:02:32 2017] ***
2017-08-21 18:02:33 compiled with version: 5.4.0 20160609 on 30 June 2017 17:32:30
2017-08-21 18:02:33 os: Linux-4.4.0-83-generic #106-Ubuntu SMP Mon Jun 26 17:54:43 UTC 2017
2017-08-21 18:02:33 nodename: harry-liveweb7
2017-08-21 18:02:33 machine: x86_64
2017-08-21 18:02:33 clock source: unix
2017-08-21 18:02:33 pcre jit disabled
2017-08-21 18:02:33 detected number of CPU cores: 2
2017-08-21 18:02:33 current working directory: (unreachable)/etc/uwsgi/vassals
2017-08-21 18:02:33 detected binary path: /usr/local/bin/uwsgi
2017-08-21 18:02:33 *** dumping internal routing table ***
2017-08-21 18:02:33 [rule: 0] subject: path_info regexp: \.svgz$ action: addheader:Content-Encoding:gzip
2017-08-21 18:02:33 *** end of the internal routing table ***
2017-08-21 18:02:33 chdir() to /home/shie/
2017-08-21 18:02:33 limiting number of processes to 15...
2017-08-21 18:02:33 your processes number limit is 15
2017-08-21 18:02:33 your memory page size is 4096 bytes
2017-08-21 18:02:33 detected max file descriptor number: 123456
2017-08-21 18:02:33 building mime-types dictionary from file /etc/mime.types...
2017-08-21 18:02:33 536 entry found
2017-08-21 18:02:33 lock engine: pthread robust mutexes
2017-08-21 18:02:33 thunder lock: disabled (you can enable it with --thunder-lock)
2017-08-21 18:02:33 uwsgi socket 0 bound to UNIX address /var/sockets/shie.pythonanywhere.com/socket fd 3
2017-08-21 18:02:33 Python version: 3.4.3 (default, Nov 17 2016, 01:12:14) [GCC 4.8.4]
2017-08-21 18:02:33 Set PythonHome to /home/shie/.virtualenvs/my-virtualenv
2017-08-21 18:02:33 *** Python threads support is disabled. You can enable it with --enable-threads ***
2017-08-21 18:02:33 Python main interpreter initialized at 0x8036b0
2017-08-21 18:02:33 your server socket listen backlog is limited to 100 connections
2017-08-21 18:02:33 your mercy for graceful operations on workers is 60 seconds
2017-08-21 18:02:33 setting request body buffering size to 65536 bytes
2017-08-21 18:02:33 mapped 333952 bytes (326 KB) for 1 cores
2017-08-21 18:02:33 *** Operational MODE: single process ***
2017-08-21 18:02:33 initialized 35 metrics
2017-08-21 18:02:33 OpenJDK 64-Bit Server VM warning:
2017-08-21 18:02:33 Can't detect initial thread stack location - find_vma failed
2017-08-21 18:02:33 WSGI app 0 (mountpoint='') ready in 1 seconds on interpreter 0x8036b0 pid: 4853 (default app)
2017-08-21 18:02:33 *** uWSGI is running in multiple interpreter mode ***
2017-08-21 18:02:33 gracefully (RE)spawned uWSGI master process (pid: 4853)
2017-08-21 18:02:33 spawned uWSGI worker 1 (pid: 4903, cores: 1)
2017-08-21 18:02:33 metrics collector thread started
2017-08-21 18:02:33 pthread_create(): Resource temporarily unavailable [core/utils.c line 3816]
2017-08-21 18:02:33 !!! unable to spawn stats pusher thread !!!
2017-08-21 18:02:33 pthread_create(): Resource temporarily unavailable [core/utils.c line 3816]
2017-08-21 18:02:33 unable to start offload thread 0 for worker 1 !!!
2017-08-21 18:02:33 spawned 0 offload threads for uWSGI worker 1
2017-08-21 18:02:33 chdir(): No such file or directory [core/uwsgi.c line 1590]
2017-08-21 18:02:33 VACUUM: unix socket /var/sockets/shie.pythonanywhere.com/socket removed.
2017-08-21 18:02:34 *** Starting uWSGI 2.0.14 (64bit) on [Mon Aug 21 18:02:33 2017] ***
2017-08-21 18:02:34 compiled with version: 5.4.0 20160609 on 30 June 2017 17:32:30
2017-08-21 18:02:34 os: Linux-4.4.0-83-generic #106-Ubuntu SMP Mon Jun 26 17:54:43 UTC 2017
2017-08-21 18:02:34 nodename: harry-liveweb7
2017-08-21 18:02:34 machine: x86_64
2017-08-21 18:02:34 clock source: unix
2017-08-21 18:02:34 pcre jit disabled
2017-08-21 18:02:34 detected number of CPU cores: 2
2017-08-21 18:02:34 current working directory: (unreachable)/etc/uwsgi/vassals
2017-08-21 18:02:34 detected binary path: /usr/local/bin/uwsgi
2017-08-21 18:02:34 *** dumping internal routing table ***
2017-08-21 18:02:34 [rule: 0] subject: path_info regexp: \.svgz$ action: addheader:Content-Encoding:gzip
2017-08-21 18:02:34 *** end of the internal routing table ***
2017-08-21 18:02:34 chdir() to /home/shie/
2017-08-21 18:02:34 limiting number of processes to 15...
2017-08-21 18:02:34 your processes number limit is 15
2017-08-21 18:02:34 your memory page size is 4096 bytes
2017-08-21 18:02:34 detected max file descriptor number: 123456
2017-08-21 18:02:34 building mime-types dictionary from file /etc/mime.types...
2017-08-21 18:02:34 536 entry found
2017-08-21 18:02:34 lock engine: pthread robust mutexes
2017-08-21 18:02:34 thunder lock: disabled (you can enable it with --thunder-lock)
2017-08-21 18:02:34 uwsgi socket 0 bound to UNIX address /var/sockets/shie.pythonanywhere.com/socket fd 3
2017-08-21 18:02:34 Python version: 3.4.3 (default, Nov 17 2016, 01:12:14) [GCC 4.8.4]
2017-08-21 18:02:34 Set PythonHome to /home/shie/.virtualenvs/my-virtualenv
2017-08-21 18:02:34 *** Python threads support is disabled. You can enable it with --enable-threads ***
2017-08-21 18:02:34 Python main interpreter initialized at 0xc806b0
2017-08-21 18:02:34 your server socket listen backlog is limited to 100 connections
2017-08-21 18:02:34 your mercy for graceful operations on workers is 60 seconds
2017-08-21 18:02:34 setting request body buffering size to 65536 bytes
2017-08-21 18:02:34 mapped 333952 bytes (326 KB) for 1 cores
2017-08-21 18:02:34 *** Operational MODE: single process ***
2017-08-21 18:02:34 initialized 35 metrics
2017-08-21 18:02:34 OpenJDK 64-Bit Server VM warning:
2017-08-21 18:02:34 Can't detect initial thread stack location - find_vma failed
2017-08-21 18:02:34 WSGI app 0 (mountpoint='') ready in 1 seconds on interpreter 0xc806b0 pid: 4906 (default app)
2017-08-21 18:02:34 *** uWSGI is running in multiple interpreter mode ***
2017-08-21 18:02:34 gracefully (RE)spawned uWSGI master process (pid: 4906)
2017-08-21 18:02:34 spawned uWSGI worker 1 (pid: 4944, cores: 1)
2017-08-21 18:02:34 metrics collector thread started
2017-08-21 18:02:34 pthread_create(): Resource temporarily unavailable [core/utils.c line 3816]
2017-08-21 18:02:34 !!! unable to spawn stats pusher thread !!!
2017-08-21 18:02:34 chdir(): No such file or directory [core/uwsgi.c line 1590]
2017-08-21 18:02:34 VACUUM: unix socket /var/sockets/shie.pythonanywhere.com/socket removed.
2017-08-21 18:02:34 pthread_create(): Resource temporarily unavailable [core/utils.c line 3816]
2017-08-21 18:02:34 unable to start offload thread 0 for worker 1 !!!
2017-08-21 18:02:34 spawned 0 offload threads for uWSGI worker 1
[changed by admin: formatting]