Re: Inconsistent stats in v$filestat

Hello Chuck:

I took a very quick look to see if there were any known issues with v$filestat and here is what I found. Not sure if this helps or not, but I come up with similar discrepancies between calculated and avgiotim. Tested on: 8.1.7 on Linux and 9.2.0 on Solaris.

Known Issues:

    The times in the WRITETIM column are often incorrect. If the average

    write time (WRITETIM/PHYWRTS) looks nonsense then it probably is.     Incorrect values typically show up as about 10 times more than one     would expect.

Regards,
-- jeff

Chuck <chuckh_at_softhome.net> wrote in message news:<Xns936598D24D465chuckhsofthomenet_at_130.133.1.4>...
> Can someone explain why the avgiotim column from v$filestat doesn't
> match the time computed by dividing total i/o's by total i/o time? Timed
> statistics is set to true. The platform is AIX 4.3, Oracle 8.1.7.
>
> col avgiotim heading "AVG|IO|TIME"
> col tot_io_time format 99999999999 heading "TOT|IO|TIME"
> col computed_avg_io_time heading 'COMPUTED|AVG IO|TIME'
>
> SELECT FILE#
> , avgiotim
> , phyrds + phywrts tot_physio
> , readtim + writetim tot_io_time
> , (readtim + writetim) / (phyrds + phywrts) computed_avg_io_time
> FROM v$filestat
> WHERE file# in (4,14)
> ORDER BY 3 DESC
> /
>
>
> AVG TOT COMPUTED
> IO IO AVG IO
> FILE# TIME TOT_PHYSIO TIME TIME
> ------ ---------- ---------- ------------ ----------
> 14 0 117405621 10124912412 86.2387365
> 4 4 320 422 1.31875
Received on Tue Apr 22 2003 - 17:01:10 CDT