Niall Litchfield wrote:
> On Aug 8, 9:14 pm, DA Morgan <damor..._at_psoug.org> wrote:
>> Niall Litchfield wrote:
>>> sybra..._at_hccnet.nl wrote:
>>>> On Wed, 08 Aug 2007 12:02:46 -0700, Teresa Masino
>>>> <teresa.mas..._at_peninsula.org> wrote:
>>>>> Alone, yea, but they can sometimes be an indicator that an instance
>>>>> needs attention.
>>>> Do you really think so? Yesterday I had a customer spouting flames
>>>> because of a RAC database coming down to a crawl due to buffer busy
>>>> waits in conjunction with both instances updating the same table over
>>>> and over again.
>>>> Nothing to be seen from the BCHR.
>>>> But then of course BCHR is a MIPS (Meaningless Indicator of the
>>>> Performance of the System).
>>>> Only good old Don Burleson makes people erroneously believe they can
>>>> tune their database by throwing memory at the problem to crank up the
>>>> BCHR.
>>>> Savy professionals (a favorite phrase of Don) know better.
>>> enough of you will recognise where I stand on ratios. Indeed I believe
>>> that I presented on the effectiveness or in fact otherwise of the BCHR
>>> on its own nearly 5 years ago.
>>> I have some sympathy withe Teresa's sentiment above though. Imagine a
>>> system that has had a truly horrible burleson concerned hopelessness
>>> ratio of 75% since 2002. Today the BCHR is 25% (or indeed 98%). I
>>> venture to suggest that it's a change worth determining the reasons for,
>>> either way. Ratios don't mean anything much, abrupt changes in them
>>> often do.
>> On the other hand monitoring things that matter would save you the
>> trouble of chasing after smoke in a house of mirrors.
>>
>> There are real things that can be monitored. And if Theresa has the
>> license to use AWR as it seems she'd be far better served looking at
>> things that matter.
>> --
>> Daniel A. Morgan
>> University of Washington
>> damor..._at_x.washington.edu (replace x with u to respond)
>> Puget Sound Oracle Users Groupwww.psoug.org- Hide quoted text -
>>
>> - Show quoted text -
>
> Indeed. And since EM will do alerts based on user defined metrics,
> it's possible the whole thing is moot.
>
> Niall
Nothing prevents you from driving your car into a telephone pole.
Smart people stay between the lines.
--
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu (replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org
Received on Thu Aug 09 2007 - 10:31:52 CDT
