From: "Kevin Grittner" <kgrittn@ymail.com>
The problem with the recommended command is that cp is not atomic.
The file can be read before the contents are materialized, causing
early end to recovery. I have seen it happen. The right way to do
this is to copy to a different name or directory and mv the file
into place once it is complete -- or use software which does that
automatically, like rsync does.
I submitted a patch a patch for this a few months ago, which is pg_copy
listed in the current CF. The patch also addresses the problem that the
archived file can get lost after power failure because it is not flushed to
disk. The patch consists of a program called pg_copy which can be used
instead of cp/copy, and a doc fix to suggest using mv. I made it following
the favorable suggestions from people.
Regards
MauMau