Service buffer overrun only when service is persistent

edit

I'm using a rospy service call to a custom c++ gazebo library. Ever time this service is called, gazebo takes a certain number of simulation steps, and responds with the new sensor measurements. I'm running many trials, so I'd like to run this as quickly as possible, so I started using persistent connections.

rospy.wait_for_service('step_service')
self.step_service = rospy.ServiceProxy('step_service', ActionService, True)
action = np.zeros((12,1))
self.state = self.step_service(action)

and my cpp service server is:

step_service = rosnode->advertiseService("/step_service", &GazeboRosStepper::step_srv, this);

bool GazeboRosStepper::step_srv(gazebo_ros_stepper::ActionService::Request  &req, gazebo_ros_stepper::ActionService::Response &res)
{
    step
    fill response with joint angles, velocities (24 doubles)
    return true
}

When the step_service in the python code is persistent, I get the errors:

rospy.service.ServiceException: service [/step_service] responded with an error: b'Buffer Overrun'

This is no matter the size of my response (I commented out most of the response, still errors) or the size of my request. It also happens during the first call.

Everything works perfectly when things are not persistent. However, since I'm calling this as fast as possible, I'd like to remove the wasted computation for resetting the TCP connection every time.