flag.StringVar(&cases,"cases","sensor_info","usecase for dataset to be imported. Multiple choices can be separated by comma, for example, -cases sensor_info,camera_detection.")
flag.IntVar(&hnum,"hnum",100,"magnification factor of the sample tables. For example, if hnum is 100 and in the sample data there are 10 tables, then 10x100=1000 tables will be created in the database.")
flag.IntVar(&vnum,"vnum",1000,"copies of the sample records in each table. If set to 0,this program will never stop simulating and importing data even if the timestamp has passed current time.")
flag.Int64Var(&delay,"delay",3*1000,"the delay millisecond to continue generate data when vnum set 0.")
flag.Int64Var(&delay,"delay",DEFAULT_DELAY,"the delay time interval(millisecond) to continue generating data when vnum set 0.")
flag.Int64Var(&tick,"tick",2000,"the tick time interval(millisecond) to print statistic info.")
flag.IntVar(&save,"save",0,"whether to save the statistical info into 'statistic' table. 0 is disabled and 1 is enabled.")
flag.IntVar(&thread,"thread",10,"number of threads to import data.")
flag.IntVar(&batch,"batch",100,"rows of records in one import batch.")
flag.IntVar(&auto,"auto",0,"whether to use the starttime and interval specified by users when simulating the data. 0 is disabled and 1 is enabled.")