Re: buffer cache hit ration calculation

From: fumi <fumi_at_tpts5.seed.net.tw>
Date: 25 Dec 1999 15:56:31 GMT
Message-ID: <842pff$jt1$1@news.seed.net.tw>

cosmin <cosmini_at_symresources.com> wrote in message news:u0P7BzVT$GA.220_at_cpmsnbbsa03...
> hello all;
>
> I am preparing for the OCP exam and I have a problem with the buffer cache
> hit ratio calculation:
>
> 1) The OCP DBA Certif Exam Guide by Couchman (ISBN 0-07-882549-0) says on
> page 875,
>
> cache hit ratio = (Physical Reads/(db block gets + consistent gets))
> * 100

There are many bugs in this book.
If you have the ability to find 200+ errors in this book, then you may be a good candidate for OCP. :)

> 2) The Oracle8 Advanced Tuning and Administration by Aronoff, Loney,
> Sonawalla (ISBN 0-07-882534-2) says on page 45
>
> cache hit ration = ((consistent gets + db block gets - physical
> gets)/(consistent gets + db block gets)) *100
>
> which one is correct?

2) is correct. Received on Sat Dec 25 1999 - 09:56:31 CST