when i use Model,then will get this error:IndexError: pop from an empty deque

[MarkLiu1]

Built web service with Flask+ uWSGI + pmml ,And enable multi-threading

file "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 982, in _get_connection
connection = self.deque.pop()
IndexError: pop from an empty deque

The complete error exception is
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 982, in _get_connection
connection = self.deque.pop()
IndexError: pop from an empty deque
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1132, in start
self.socket.connect((self.address, self.port))
ConnectionRefusedError: [Errno 111] Connection refused
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "app.py", line 346, in get_model_result_v2
result = fd.predict(req_json)
File "./fkdqv11v12rhmodelscore_S1_0/fkdqv11v12rhmodelscore_S1_0.py", line 401, in predict
features_pd_model = self._derive(data)
File "./fkdqv11v12rhmodelscore_S1_0/fkdqv11v12rhmodelscore_S1_0.py", line 337, in _derive
result_v12 = self._derive_v12(data)
File "./fkdqv11v12rhmodelscore_S1_0/fkdqv11v12rhmodelscore_S1_0.py", line 198, in _derive_v12
lgb_v12_model_1_prob = lgb_v12_model_1.predict(res)['probability(1)']
File "/usr/local/lib/python3.7/site-packages/pypmml/model.py", line 155, in predict
return self.call('predict', data)
File "/usr/local/lib/python3.7/site-packages/pypmml/base.py", line 134, in call
return call_java_func(getattr(self._java_model, name), *a)
File "/usr/local/lib/python3.7/site-packages/pypmml/base.py", line 41, in call_java_func
return _java2py(func(*args))
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1314, in call
args_command, temp_args = self._build_args(*args)
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1277, in _build_args
(new_args, temp_args) = self._get_args(args)
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1264, in _get_args
temp_arg = converter.convert(arg, self.gateway_client)
File "/usr/local/lib/python3.7/site-packages/py4j/java_collections.py", line 521, in convert
java_map = HashMap()
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1586, in call
answer = self._gateway_client.send_command(command)
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1036, in send_command
connection = self._get_connection()
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 984, in _get_connection
connection = self._create_connection()
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 990, in _create_connection
connection.start()
File "/usr/local/lib/python3.7/site-packages/py4j/java_gateway.py", line 1144, in start
raise Py4JNetworkError(msg, e)
py4j.protocol.Py4JNetworkError: An error occurred while trying to connect to the Java server (127.0.0.1:41543)

[scorebot]

It seems an issue of py4j that is used by pypmml, there is a related issue: py4j/py4j#325
You can try to increase memory for JVM, for example:

import os
os.environ['JAVA_OPTS'] = '-Xms1g -Xmx4g'