Currently, WAL files will be archived as soon as archive_command is set.
IMHO, this is not desirable if no permanent backup is wanted, but only
scheduled online backup because; it will flood the wal_archive
destination with files that will never be used.
I propose to introduce a GUC "permanent_archiving" or so, to select
whether wal archiving happens permanently or only when a backup is in
progress (i.e. between pg_start_backup and pg_stop_backup).
Regards,
Andreas