You can control the time window of your search, e.g. if you set the earliest to be -4h@h and the latest to be @h , e.g.
earliest=-4h@h latest=@h
then you will get the previous 4 hours up to the last completed hour
Thanks for your help. But I need to use it in tstats command, and it will give error "'tstats' command: Invalid argument: 'earliest=-4h@h'" Do you know any other way. Better it can use in time picker as well.