The logfile stop upgrade after a vim write

[lz ma <ma100@xxxxxxxxxxx>]

1.  pg_ctl -D data -l  MyLog
2.  vim MyLog : add some words, save and exit
3. after vim operation, MyLog will never upgrade except restart server

I know it caused by file descripter only open once at the start by postgres, and vim operation rename the file to MyLog~, so postgres can't upgrade