Hello
Empty archive_command with archive_mode = on prohibits purge old WAL.
If you will use archive_mode - you must provide correct command in archive_command (change archive_command need only
reload).Documentation can be found here:
https://www.postgresql.org/docs/current/static/continuous-archiving.html#BACKUP-ARCHIVING-WAL
Otherwise you must disable archive_mode (need restart) or use archive_command with any command returning 0. For example
archive_command= '/bin/true'. This is useful if you wish enable WAL archiving later without restart postgresql.
regards, Sergei
