servers.py运行后频繁报错:No JSON object could be decoded

[skytt]

WARNING:root:send_command response
Traceback (most recent call last):
File "/root/shadowsocks-rm/shadowsocks/dbtransfer.py", line 190, in thread_db
DbTransfer.del_server_out_of_bound_safe(rows)
File "/root/shadowsocks-rm/shadowsocks/dbtransfer.py", line 160, in del_server_out_of_bound_safe
server = json.loads(DbTransfer.get_instance().send_command('stat: {"server_port":%s}' % row[0]))
File "/usr/lib64/python2.7/json/init.py", line 338, in loads
return _default_decoder.decode(s)
File "/usr/lib64/python2.7/json/decoder.py", line 365, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib64/python2.7/json/decoder.py", line 383, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded
WARNING:root:db thread except:No JSON object could be decoded
WARNING:root:send_command response
Traceback (most recent call last):
File "/root/shadowsocks-rm/shadowsocks/dbtransfer.py", line 190, in thread_db
DbTransfer.del_server_out_of_bound_safe(rows)
File "/root/shadowsocks-rm/shadowsocks/dbtransfer.py", line 160, in del_server_out_of_bound_safe
server = json.loads(DbTransfer.get_instance().send_command('stat: {"server_port":%s}' % row[0]))
File "/usr/lib64/python2.7/json/init.py", line 338, in loads
return _default_decoder.decode(s)
File "/usr/lib64/python2.7/json/decoder.py", line 365, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib64/python2.7/json/decoder.py", line 383, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded
WARNING:root:db thread except:No JSON object could be decoded

主服务器正常，这个附服务器接入的时候就会这样，可以正常显示一会的在线人数、负载等情况，但是过一会之后就提示:No JSON object could be decoded。尝试自查代码解决找不出原因……烦请帮助，感激不尽！

看到先前的提问通过升级Python解决，可是我的已经是2.7.5，问题依旧……