Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Why are people so afraid of underscore parameters ?

Re: Why are people so afraid of underscore parameters ?

From: Pete Sharman <peter.sharman_at_oracle.com>
Date: 23 Aug 2002 08:06:48 -0700
Message-ID: <ak5j280u1o@drn.newsguy.com>


In article <c6f99.12411$g9.40345_at_newsfeeds.bigpond.com>, "Richard says...
>
>Hi Bass,
>
>Aren't some people weird.
>
>I'm personally afraid of the dark, spiders, any insect larger than my little
>finger, heights, death, Mike Tyson (closely related to the previous one I
>know), sharks that I don't see, bagpipes, Pete Sharman and people in general
>who look at me kinda funny.

Hmm, does that mean I count as one of the people in general who look at you "kinda funny"? ;)

Otherwise, generally sound advice as usual. One comment I would add is that it's a hell of a lot easier to say don't change any of them than to document which ones could be changed under which circumstances. I think it's best to say leave them alone unless Support tells you otherwise.

Pete
>
>But to be afraid of _parameters, well that's really quite bizarre ;)
>
>Actually, I think both your Boss, yourself and Oracle are all correct in
>your own ways.
>
>I would suggest, that the vast majority of the _parameters in the vast
>majority of cases do not have to be touched at all. I would also suggest
>that the vast majority of the parameters if modified would have a more
>probable chance of doing harm than good. If most of these were to be
>documented, I can tell you now, the number of calls and tars that Oracle
>Support would have to deal with would escalate to scary proportions. So I
>completely agree with Oracle 'hiding' these parameters and documenting and
>hence encouraging us to use and modify only those parameters that have a
>greater chance of making a positive outcome in our environments.
>
>Therefore I agree with the cautious approach being adopted by your boss. If
>you never touch an _parameter, you're going to reduce the chances of any
>significant stuff-ups, stuff-ups that Oracle Support may not take too kindly
>on.
>
>However, the are some situations when the modification of these parameters
>is beneficial and in fact recommend. There was a thread here not too long
>ago on the positive impact of changing the _spin_count parameter. Usually
>shouldn't be touched, probably would hurt rather than improve performance if
>touched without due care but could result in a positive return if modified
>in certain situations appropriately. Therefore, you are potentially correct
>to suggest the odd tweak here or there and your boss is being somewhat
>pedantic by saying never. However, such changes should have the following
>'steps' associated with them.
>
>1) A clear understanding on the use of the particular parameter and it's
>possible effects.
>
>2) A clear objective for the changing of such a parameter
>
>3) A demonstrated benefit in (preferably in a test environment first) for
>such a change and a clear demonstration of no significant side-effects
>
>4) A 'chat' to Oracle Support regarding the change and some form of
>confirmation that your tack has some merit and chance of success
>
>5) Clear documentation on the parameter change, date of effect, reasoning
>for change and verifiable effect of the change
>
>Although all the above are not strictly required and in some cases not
>practical or achievable, at least going through the thought process suggests
>you haven't made a change for change sake and should satisfy your boss on
>your motives and course of action.
>
>My thoughts
>
>Cheers
>
>Richard
>
>
>"Bass Chorng" <bchorng_at_yahoo.com> wrote in message
>news:bd9a9a76.0208221016.3f3f9dcf_at_posting.google.com...
>> My boss does not allow DBAs to use any underscore parameters.
>> He seems to be unreasonably freaked out upon hearing one.
>>
>> Some also advise that you should never use it without being
>> instructed by Oracle Support.
>>
>> A lot of good tuning parameters in 8i have gone undergound in 9i.
>> Some parameters have stayed undergound since Oracle 7 but really
>> should be normalized, such as _trace_files_public which I see
>> no reason to be hidden. I have never seen a single
>> production site not using that (except current one). It is a no
>> brainer parameter.
>>
>> I know hidden parameters were initially used by developers.
>> They got released without adequate documentation. Later on
>> Oracle moves normal parameters undergound in new releases
>> because the functionality of such parameters were deminished or
>> probably just to reduce the number of visible parameters for
>> better looks and easier documentation.
>>
>> In 8.0.5, there are 141 underscore parameters, in 8.1.7, it
>> becomes 301, in 9.2.0, it is 544. All it tells me is, that
>> Oracle just keeps on moving parameters undergound to keep
>> the other side slim.
>>
>> But to say that Oracle does NOT support them is just not true.
>> ( This has nothing to do with some specific underscore parameters
>> that they do not support such as _disable_logging )
>> I have used numours underscore parameters per Oracle's suggestions.
>>
>> I think if you know what a parameter does and you know that is
>> what you need, there really is no need to treat tham as taboos.
>> You can do damage to your database too with normal parameters if you
>> don't know what you are doing. Oracle obsoletes parameters on either
>> side the same way.
>>
>> If you disagree, I like to hear your comments.
>
>

HTH. Additions and corrections welcome.

Pete

SELECT standard_disclaimer, witty_remark FROM company_requirements; Received on Fri Aug 23 2002 - 10:06:48 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US