TBH, it looks like it has actually saved a string
containing "[object Object]",
Try
msg.payload={}
msg.payload.agvName = msg.agv.config.name;
msg.payload.agvVerbose = msg.agv.AIC.verbose;
msg.payload.agv = msg.agv;
msg.topic="INSERT INTO unit_1.agv_verbose (log_id, log_ts, agv_name, status_line, agv_obj) VALUES (uuID(), current_timestamp(), :agvName, :agvVerbose, :agv);"
return msg;
↑ you should not need to turn the object into a string (and your method doesnt actually work)
So the above should work but if not, you can always "force it" ↓
msg.payload={}
msg.payload.agvName = msg.agv.config.name;
msg.payload.agvVerbose = msg.agv.AIC.verbose;
msg.payload.agv = JSON.stringify(msg.agv);
msg.topic="INSERT INTO unit_1.agv_verbose (log_id, log_ts, agv_name, status_line, agv_obj) VALUES (uuID(), current_timestamp(), :agvName, :agvVerbose, :agv);"
return msg;