Troubleshooting ArcGIS Online VRP requests

[IhabElAttar]

Hello Everyone,

I have been generating synchronous requests to the ArcGIS Online VRP solver using a node server for almost two years. Recently I changed the server to start optimizing a fleet of multiple drivers . Some of the requests i send tend to fail. Upon checking the "out_unassigned_stops" . All the stops have  "ViolatedConstraint" attribute set to null. How to troubleshoot this ? In the case when the violated constraint is set to a number, is there a way to know what specific constraint(s) were violated ? For how long are the results of a failed or successful asynchoronous job stored on ArcGIS Online? Does it cost credits to fetch the results ?  How does the solver behave when the request is missing a parameter that cannot be null ? does it use the default value or just fail to solve  without reporting that a mandatory parameter is missing ?

I provided a sample request below in case anyone can pinpoint a reason for this request to fail

{"token":"DnLf299qf-vat5Uq72DyOlSM94CVKxIa9dPBA3nYspIMNx-aqw_y23bogS5Nh6OIHrmAUyk46EQ..","default_date":1581694380000,"f":"json","travel_mode":"CUSTOM","distance_units":"Kilometers","time_units":"Minutes","time_zone_usage_for_time_fields":"UTC","excess_transit_factor":"Low","populate_directions":true,"directions_style_name":"NA Navigation","restrictions":"["Avoid Carpool Roads","Avoid Toll Roads","Avoid Gates","Avoid Private Roads","Avoid Unpaved Roads","Driving an Automobile","Roads Under Construction Prohibited","Through Traffic Prohibited"]","attribute_parameter_values":"{"features":[{"attributes":{"AttributeName":"Avoid Toll Roads","ParameterName":"Restriction Usage","ParameterValue":"PROHIBITED"}}]}","time_window_factor":"low","depots":"{"features":[{"geometry":{"x":"-79.2490088","y":"43.935533"},"attributes":{"Name":"239"}},{"geometry":{"x":"-79.4642189","y":"43.7595333"},"attributes":{"Name":"417"}},{"geometry":{"x":"-79.693544","y":"43.6406799"},"attributes":{"Name":"3363"}},{"geometry":{"x":"-79.4705623","y":"43.7784275"},"attributes":{"Name":"3370"}},{"geometry":{"x":"-79.4514615","y":"43.8705282"},"attributes":{"Name":"3838"}},{"geometry":{"x":"-79.4379013","y":"43.8889058"},"attributes":{"Name":"3988"}},{"geometry":{"x":"-79.525831","y":"43.7546165"},"attributes":{"Name":"4002"}},{"geometry":{"x":"-79.3809567","y":"43.6498771"},"attributes":{"Name":"4095"}}]}","orders":"{"features":[{"geometry":{"x":"-79.3274","y":"43.8381"},"attributes":{"Name":"P-7503176","TimeWindowStart1":1581696000000,"ServiceTime":"5","TimeWindowEnd1":1581714000000}},{"geometry":{"x":"-79.2318","y":"43.7843"},"attributes":{"Name":"D-7503176","RouteName":"null","ServiceTime":"5","TimeWindowEnd1":1581703200000}},{"geometry":{"x":"-79.2318","y":"43.7843"},"attributes":{"Name":"P-7503199","TimeWindowStart1":1581701400000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3274","y":"43.8381"},"attributes":{"Name":"D-7503199","ServiceTime":"5","TimeWindowEnd1":1581708600000}},{"geometry":{"x":"-79.2802","y":"43.7635"},"attributes":{"Name":"P-7504078","TimeWindowStart1":1581691500000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3261","y":"43.8358"},"attributes":{"Name":"D-7504078","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.323","y":"43.8392"},"attributes":{"Name":"D-7502144","RouteName":"239","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.2446","y":"43.9718"},"attributes":{"Name":"D-7502148","RouteName":"239","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3857","y":"43.8672"},"attributes":{"Name":"D-7502153","RouteName":"239","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3557","y":"43.7616"},"attributes":{"Name":"D-7503986","RouteName":"239","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4686","y":"43.7685"},"attributes":{"Name":"P-7503905","TimeWindowStart1":1581688260000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3655","y":"43.6549"},"attributes":{"Name":"D-7503905","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5259","y":"43.8009"},"attributes":{"Name":"P-7503994","TimeWindowStart1":1581689700000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3444","y":"43.679"},"attributes":{"Name":"D-7503994","ServiceTime":"5","TimeWindowEnd1":1581704100000}},{"geometry":{"x":"-79.5492","y":"43.8029"},"attributes":{"Name":"P-7504019","TimeWindowStart1":1581690600000,"ServiceTime":"5","TimeWindowEnd1":1581710400000}},{"geometry":{"x":"-79.4024","y":"43.6434"},"attributes":{"Name":"D-7504019","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4949","y":"43.7897"},"attributes":{"Name":"P-7504079","TimeWindowStart1":1581692400000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3802","y":"43.6578"},"attributes":{"Name":"D-7504079","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5534","y":"43.7661"},"attributes":{"Name":"P-7504089","TimeWindowStart1":1581691320000,"ServiceTime":"5","TimeWindowEnd1":1581715800000}},{"geometry":{"x":"-79.3798","y":"43.6487"},"attributes":{"Name":"D-7504089","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4673","y":"43.8425"},"attributes":{"Name":"P-7504145","TimeWindowStart1":1581692460000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3834","y":"43.648"},"attributes":{"Name":"D-7504145","ServiceTime":"5","TimeWindowEnd1":1581706860000}},{"geometry":{"x":"-79.4929","y":"43.7962"},"attributes":{"Name":"P-7504197","TimeWindowStart1":1581693120000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.37","y":"43.6499"},"attributes":{"Name":"D-7504197","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.728","y":"43.8649"},"attributes":{"Name":"D-7503802","RouteName":"417","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6212","y":"43.7721"},"attributes":{"Name":"D-7503955","RouteName":"417","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6932","y":"43.6407"},"attributes":{"Name":"P-7502763","TimeWindowStart1":1581690240000,"ServiceTime":"5","TimeWindowEnd1":1581715800000}},{"geometry":{"x":"-79.4572","y":"43.7027"},"attributes":{"Name":"D-7502763","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6253","y":"43.6421"},"attributes":{"Name":"P-7503710","TimeWindowStart1":1581692400000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4994","y":"43.8205"},"attributes":{"Name":"D-7503710","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6838","y":"43.6598"},"attributes":{"Name":"P-7504004","TimeWindowStart1":1581689880000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5","y":"43.8024"},"attributes":{"Name":"D-7504004","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.62","y":"43.742"},"attributes":{"Name":"P-7504053","TimeWindowStart1":1581690720000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4916","y":"43.7245"},"attributes":{"Name":"D-7504053","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.62","y":"43.742"},"attributes":{"Name":"P-7504125","TimeWindowStart1":1581692040000,"ServiceTime":"0","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4981","y":"43.7952"},"attributes":{"Name":"D-7504125","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4738","y":"43.7673"},"attributes":{"Name":"D-7503996","RouteName":"3363","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4671","y":"43.7697"},"attributes":{"Name":"D-7504021","RouteName":"3363","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.4632","y":"43.6973"},"attributes":{"Name":"P-7504189","TimeWindowStart1":1581692940000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4729","y":"43.8272"},"attributes":{"Name":"D-7504189","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4606","y":"43.7218"},"attributes":{"Name":"D-7503907","RouteName":"3370","ServiceTime":"5","TimeWindowEnd1":1581697380000}},{"geometry":{"x":"0","y":"0"},"attributes":{"Name":"D-7503911","RouteName":"3370","ServiceTime":"5","TimeWindowEnd1":1581706380000}},{"geometry":{"x":"-79.38","y":"43.864"},"attributes":{"Name":"P-7504028","TimeWindowStart1":1581690360000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.39","y":"43.6436"},"attributes":{"Name":"D-7504028","ServiceTime":"5","TimeWindowEnd1":1581704760000}},{"geometry":{"x":"-79.3795","y":"43.8663"},"attributes":{"Name":"P-7504086","TimeWindowStart1":1581691200000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3936","y":"43.6719"},"attributes":{"Name":"D-7504086","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3923","y":"43.8508"},"attributes":{"Name":"P-7504095","TimeWindowStart1":1581691500000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3877","y":"43.6506"},"attributes":{"Name":"D-7504095","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3778","y":"43.8474"},"attributes":{"Name":"P-7504345","TimeWindowStart1":1581693960000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3609","y":"43.6541"},"attributes":{"Name":"D-7504345","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3857","y":"43.8453"},"attributes":{"Name":"P-7504350","TimeWindowStart1":1581694080000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3796","y":"43.6472"},"attributes":{"Name":"D-7504350","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3869","y":"43.6593"},"attributes":{"Name":"D-7503848","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3891","y":"43.657"},"attributes":{"Name":"D-7504196","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.3897","y":"43.6577"},"attributes":{"Name":"D-7504204","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.3869","y":"43.6593"},"attributes":{"Name":"D-7504212","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.3891","y":"43.657"},"attributes":{"Name":"D-7504222","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.3901","y":"43.6594"},"attributes":{"Name":"D-7504331","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.3773","y":"43.6537"},"attributes":{"Name":"D-7504339","RouteName":"3838","ServiceTime":"5","TimeWindowEnd1":1581742740000}},{"geometry":{"x":"-79.0651","y":"43.8275"},"attributes":{"Name":"P-7502068","TimeWindowStart1":1581688800000,"ServiceTime":"5","TimeWindowEnd1":1581703200000}},{"geometry":{"x":"-79.3806","y":"43.8609"},"attributes":{"Name":"D-7502068","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.337","y":"43.7743"},"attributes":{"Name":"P-7504101","TimeWindowStart1":1581691620000,"ServiceTime":"5","TimeWindowEnd1":1581710400000}},{"geometry":{"x":"-78.9421","y":"43.8993"},"attributes":{"Name":"D-7504101","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5004","y":"43.8367"},"attributes":{"Name":"P-7503934","TimeWindowStart1":1581688740000,"ServiceTime":"5","TimeWindowEnd1":1581714000000}},{"geometry":{"x":"-79.664","y":"43.7852"},"attributes":{"Name":"D-7503934","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4738","y":"43.7799"},"attributes":{"Name":"P-7504008","TimeWindowStart1":1581689940000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6756","y":"43.6698"},"attributes":{"Name":"D-7504008","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4739","y":"43.7799"},"attributes":{"Name":"P-7504218","TimeWindowStart1":1581693480000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.7529","y":"43.6959"},"attributes":{"Name":"D-7504218","RouteName":"null","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4919","y":"43.8333"},"attributes":{"Name":"P-7504221","TimeWindowStart1":1581693540000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.672","y":"43.6925"},"attributes":{"Name":"D-7504221","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5438","y":"43.7967"},"attributes":{"Name":"P-7504343","TimeWindowStart1":1581693900000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6149","y":"43.7507"},"attributes":{"Name":"D-7504343","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5252","y":"43.8085"},"attributes":{"Name":"P-7504351","TimeWindowStart1":1581694080000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.7356","y":"43.6675"},"attributes":{"Name":"D-7504351","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.5266","y":"43.7553"},"attributes":{"Name":"D-7503225","RouteName":"4002","ServiceTime":"5","TimeWindowEnd1":1581699600000}},{"geometry":{"x":"-79.7208","y":"43.6857"},"attributes":{"Name":"D-7503852","RouteName":"4002","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.4625","y":"43.8083"},"attributes":{"Name":"D-7503940","RouteName":"4002","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.7569","y":"43.5975"},"attributes":{"Name":"D-7503973","RouteName":"4002","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.3777","y":"43.6488"},"attributes":{"Name":"P-7503883","TimeWindowStart1":1581687540000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6417","y":"43.5959"},"attributes":{"Name":"D-7503883","ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.353","y":"43.7044"},"attributes":{"Name":"P-7504112","TimeWindowStart1":1581692400000,"ServiceTime":"5","TimeWindowEnd1":1581717600000}},{"geometry":{"x":"-79.6521","y":"43.5742"},"attributes":{"Name":"D-7504112","ServiceTime":"5","TimeWindowEnd1":1581710400000}},{"geometry":{"x":"-79.38","y":"43.6481"},"attributes":{"Name":"D-7503758","RouteName":"4095","ServiceTime":"5","TimeWindowEnd1":1581703800000}},{"geometry":{"x":"-79.3796","y":"43.6472"},"attributes":{"Name":"D-7503866","RouteName":"4095","ServiceTime":"5","TimeWindowEnd1":1581694980000}},{"geometry":{"x":"-79.2379","y":"43.7202"},"attributes":{"Name":"D-7504056","RouteName":"4095","ServiceTime":"5","TimeWindowEnd1":1581699720000}}]}","routes":"{"features":[{"attributes":{"Name":"239","StartDepotName":"239","MaxOrderCount":"30","EarliestStartTime":1581694380000,"LatestStartTime":1581694380000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"417","StartDepotName":"417","MaxOrderCount":"30","EarliestStartTime":1581694380000,"LatestStartTime":1581694380000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"3363","StartDepotName":"3363","MaxOrderCount":"30","EarliestStartTime":1581694380000,"LatestStartTime":1581694380000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"3370","StartDepotName":"3370","MaxOrderCount":"30","EarliestStartTime":1581694260000,"LatestStartTime":1581694260000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"3838","StartDepotName":"3838","MaxOrderCount":"30","EarliestStartTime":1581694380000,"LatestStartTime":1581694380000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"3988","StartDepotName":"3988","MaxOrderCount":"30","EarliestStartTime":1581694380000,"LatestStartTime":1581694380000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"4002","StartDepotName":"4002","MaxOrderCount":"30","EarliestStartTime":1581694080000,"LatestStartTime":1581694080000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}},{"attributes":{"Name":"4095","StartDepotName":"4095","MaxOrderCount":"30","EarliestStartTime":1581694380000,"LatestStartTime":1581694380000,"CostPerUnitTime":"0.42","CostPerUnitDistance":"0.95"}}]}","order_pairs":"{"features":[{"attributes":{"FirstOrderName":"P-7503176","SecondOrderName":"D-7503176"}},{"attributes":{"FirstOrderName":"P-7503199","SecondOrderName":"D-7503199"}},{"attributes":{"FirstOrderName":"P-7504078","SecondOrderName":"D-7504078"}},{"attributes":{"FirstOrderName":"P-7503905","SecondOrderName":"D-7503905"}},{"attributes":{"FirstOrderName":"P-7503994","SecondOrderName":"D-7503994"}},{"attributes":{"FirstOrderName":"P-7504019","SecondOrderName":"D-7504019"}},{"attributes":{"FirstOrderName":"P-7504079","SecondOrderName":"D-7504079"}},{"attributes":{"FirstOrderName":"P-7504089","SecondOrderName":"D-7504089"}},{"attributes":{"FirstOrderName":"P-7504145","SecondOrderName":"D-7504145"}},{"attributes":{"FirstOrderName":"P-7504197","SecondOrderName":"D-7504197"}},{"attributes":{"FirstOrderName":"P-7502763","SecondOrderName":"D-7502763"}},{"attributes":{"FirstOrderName":"P-7503710","SecondOrderName":"D-7503710"}},{"attributes":{"FirstOrderName":"P-7504004","SecondOrderName":"D-7504004"}},{"attributes":{"FirstOrderName":"P-7504053","SecondOrderName":"D-7504053"}},{"attributes":{"FirstOrderName":"P-7504125","SecondOrderName":"D-7504125"}},{"attributes":{"FirstOrderName":"P-7504189","SecondOrderName":"D-7504189"}},{"attributes":{"FirstOrderName":"P-7504028","SecondOrderName":"D-7504028"}},{"attributes":{"FirstOrderName":"P-7504086","SecondOrderName":"D-7504086"}},{"attributes":{"FirstOrderName":"P-7504095","SecondOrderName":"D-7504095"}},{"attributes":{"FirstOrderName":"P-7504345","SecondOrderName":"D-7504345"}},{"attributes":{"FirstOrderName":"P-7504350","SecondOrderName":"D-7504350"}},{"attributes":{"FirstOrderName":"P-7502068","SecondOrderName":"D-7502068"}},{"attributes":{"FirstOrderName":"P-7504101","SecondOrderName":"D-7504101"}},{"attributes":{"FirstOrderName":"P-7503934","SecondOrderName":"D-7503934"}},{"attributes":{"FirstOrderName":"P-7504008","SecondOrderName":"D-7504008"}},{"attributes":{"FirstOrderName":"P-7504218","SecondOrderName":"D-7504218"}},{"attributes":{"FirstOrderName":"P-7504221","SecondOrderName":"D-7504221"}},{"attributes":{"FirstOrderName":"P-7504343","SecondOrderName":"D-7504343"}},{"attributes":{"FirstOrderName":"P-7504351","SecondOrderName":"D-7504351"}},{"attributes":{"FirstOrderName":"P-7503883","SecondOrderName":"D-7503883"}},{"attributes":{"FirstOrderName":"P-7504112","SecondOrderName":"D-7504112"}}]}"}

Thanks,

Ihab

[ShubhadaKshirsagar]

Hello Ihab,

I am able to run this on the online VRP solver, the error is "Order D-7503911 is unlocated". Please check your inputs - "{"geometry":{"x":"0","y":"0"},"attributes":{"Name":"D-7503911","RouteName":"3370","ServiceTime":"5","TimeWindowEnd1":1581706380000}}" and x, y coordinates seem to be wrong for your analysis.

For your other questions-
How to troubleshoot this? In the case when the violated constraint is set to a number, is there a way to know what specific constraint(s) were violated ? - There is a section on troubleshooting at the end of this help page - https://developers.arcgis.com/rest/network/api-reference/vehicle-routing-problem-service.htm

For how long are the results of a failed or successful asynchoronous job stored on ArcGIS Online? - 24 hours on logistics.arcgis.com

Does it cost credits to fetch the results ? - The credits are charged only for running jobs, no credits for fetching results.

How does the solver behave when the request is missing a parameter that cannot be null ? does it use the default value or just fail to solve without reporting that a mandatory parameter is missing ? - Some params have defualt values and some throw an error when mandatory parameter is not entered. For more details - https://developers.arcgis.com/rest/network/api-reference/vehicle-routing-problem-service.htm