b=$(date +%Y%m%d%H%M%S)
mkdir -p /mnt/save/$b
pg_dump $DATABASE_URL --clean > /mnt/save/$b/pg.dump \
   || ( 
      rm -rf /mnt/save/$b
      echo "backup failed; deleting $b"
      exit 1
   )
if du -sh /mnt/save/$b | grep -Ei "^[ ]*(4|2.).0K"; then 
   rm -rf /mnt/save/$b
   echo rm empty backup $b
fi