"No such file or directory" error when reading free space information

[a1exsh]

Just got this failure on v1.3.1. Was running fine for some minutes and then crashed:

02-28 15:12:52,312 Unable to read free space information for the pg_xlog and data directories for the directory             /home/postgres/pgdata/pgroot/data: [Errno 2] No such file or directory: '/home/postgres/pgdata/pgroot/data/pg_xlog/.wal-e/prefetch/running/000000010001EB100000008B'
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/pg_view/__init__.py", line 278, in main
    loop(collectors, consumer, groups, output_method)
  File "/usr/local/lib/python3.5/dist-packages/pg_view/__init__.py", line 90, in loop
    curses.wrapper(do_loop, groups, output_method, collectors, consumer)
  File "/usr/lib/python3.5/curses/__init__.py", line 94, in wrapper
    return func(stdscr, *args, **kwds)
  File "/usr/local/lib/python3.5/dist-packages/pg_view/__init__.py", line 142, in do_loop
    process_single_collector(st)
  File "/usr/local/lib/python3.5/dist-packages/pg_view/utils.py", line 84, in process_single_collector
    st.diff()
  File "/usr/local/lib/python3.5/dist-packages/pg_view/collectors/base_collector.py", line 761, in diff
    candidate = self._produce_diff_row(prev, cur)
  File "/usr/local/lib/python3.5/dist-packages/pg_view/collectors/base_collector.py", line 371, in _produce_diff_row
    None) is not None else None)
  File "/usr/local/lib/python3.5/dist-packages/pg_view/collectors/partition_collector.py", line 169, in calculate_time_until_full
    prev.get('path_size', 0) > 0 and
TypeError: unorderable types: NoneType() > int()

Looks like a race condition with listing directory contents and trying to get size information on individual files in the loop.

[tmotyl]

I've got the same issue with v 1.4.1 on python 2.7

ERROR: 2021-07-16 16:54:58,137 Unable to read free space information for the pg_xlog and data directories for the directory             /var/lib/postgresql/11/main: [Errno 2] No such file or directory: '/var/lib/postgresql/11/main/pg_xlog/'

[tmotyl]

duplicate? #82