Is recommendation letter a completely professional thing or keeping good personal relation with the writer required? Is recommendation letter (faculty position) a completely professional thing ? I mean I completed PhD one year ago, I had good relation with my Phd advisor when I was his student. After that I left my country for postdoc and obviously the relation is not like earlier. Does keeping good relation influences recommendation letter or it is completely professional thing ?
If you did well during your PhD (and did not have a fight with your supervisor afterwards), your supervisor should write a good recommendation letter. Recommendation letters are professional and you do not need to keep a good personal relation. It happens often that people have to ask for recommendation letters some time after moving on to somewhere else.

The only advantage of being still there could be that it would make it easier to remind your supervisor if he takes too long to write the letter.