Seafile not response, seaf-server or ccnet-server has many process

Seafile 6.2.13
Ubuntu 14.04
database was sqlite3 export to mysql

every hour seaf-server or ccnet-server create multi process, then Seafile not response , need kill process to fix this problem.

2018-08-08 11:32:03 seaf-server 25860 process count 29
2018-08-08 12:31:03 seaf-server 27951 process count 29
2018-08-08 13:34:02 seaf-server 29599 process count 29
2018-08-08 14:13:43 seaf-server 31328 process count 29
2018-08-08 17:49:02 seaf-server 32475 process count 29

root@seafilepro:~# pip list
apt-xapian-index (0.45)
argparse (1.2.1)
boto (2.49.0)
captcha (0.2.4)
chardet (2.0.1)
colorama (0.2.5)
configobj (4.7.2)
decorator (4.0.11)
django-pylibmc (0.6.1)
html5lib (0.999)
imageio (2.1.2)
Ksplice-Uptrack (1.2.49)
Landscape-Client (14.12)
moviepy (0.2.3.2)
MySQL-python (1.2.3)
numpy (1.14.0)
PAM (0.4.2)
Pillow (5.2.0)
pip (1.5.4)
py (1.4.22)
pycurl (7.19.3)
pylibmc (1.5.2)
pyOpenSSL (0.13)
pyserial (2.6)
pytest (2.6.0)
python-apt (0.9.3.5ubuntu3)
python-debian (0.1.21-nmu2ubuntu2)
python-ldap (2.4.10)
python-memcached (1.53)
PyYAML (3.10)
requests (2.2.1)
requests-oauthlib (1.0.0)
setuptools (40.0.0)
six (1.5.2)
ssh-import-id (3.21)
tqdm (4.11.2)
Twisted-Core (13.2.0)
uno (0.3.3)
urllib3 (1.23)
virtualenv (16.0.0)
wheel (0.24.0)
wsgiref (0.1.2)
zope.interface (4.0.5)