v$filestat and file efficiency

Greetings all,

Can anyone tell me the difference between the columns: phywrts and phyblkwrt from the v$filestat view? I have a query that shows file efficiency and I am trying to gain an understanding of what this efficiency value represents and how it can be improved. Here is the query that produces the efficiency report:

SELECT

        f.tablespace_name         ts


      , f.file_name               fn


      , v.phyrds                  rds


      , v.phyblkrd                blk_rds


      , v.phywrts                 wrts


      , v.phyblkwrt               blk_wrts


      , v.phyrds + v.phywrts      rw


      , v.phyblkrd + v.phyblkwrt  blk_rw


      , DECODE(v.phyblkrd, 0, null,


        ROUND(100*(v.phyrds + v.phywrts)/
                  (v.phyblkrd + v.phyblkwrt), 2 )) eff
    FROM
        dba_data_files f


      , v$filestat       v


    WHERE
        f.file_id = v.file#
    ORDER BY ts

Any help with understanding file efficiency would be greatly appreciated!

regards,
jeff

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