Re: Read Hit Ratio Question- Suggestions Welcome.

Tapan

One possibility is that the value of the column has gone past it's maximum, and it's wrapping. Due to the binary arithmetic being done, you'll see negative values when this occurs.

HTH. Pete

Tapan Trivedi wrote:

> Hey Gurus,
> I am doing this query to find out the Read Hit ratios on a Baseline
> system (upon which further development will be done) .
>
> select 1-(sum(decode(name, 'physical reads', value,0))/
> (sum(decode(name, 'db block gets', value,0)) +
> (sum(decode(name, 'consistent gets', value,0))))) * 100
> "Read Hit Ratio"
> from v$sysstat;
>
> I am getting very weird results on about four systems on which I have
> run the queries . I am getting NEGATIVE, yes, NEGATIVE results. What
> does this mean ?
>
> I am getting values like
> -.047
> -18.99
> -2.31
> -.69 etc.
>
> What does this mean ?
>
> Tapan

--
Regards

Pete

Received on Thu Aug 05 1999 - 11:25:39 CDT