text: -- ********************************************************************************************************
  --  filename: data_turnaround.sql
  --  version(s): 11, 12, 13, 14
  --  preReqs: none 
  -- ********************************************************************************************************
  --
  --  Results:
  --
  --  bytes/mbytes/gbytes the pg wal has progressed since lsn '0/0' (installation time)
  --  if collected over time gives an indication how many insert/update/delete activity is handled
  --
  -- ********************************************************************************************************
  SELECT
       a.total_bytes,
      (a.total_bytes / 1024 / 1024)::bigint AS mbytes,
      (a.total_bytes / 1024 ^ 3)::bigint AS gbytes
  FROM
      pg_wal_lsn_diff (pg_current_wal_lsn (), '0/0') a (total_bytes);
  