[askdba] Re: Need help with Interview Questions
- From: Ganesh Raja <ganesh.raja@xxxxxxxxx>
- To: askdba@xxxxxxxxxxxxx
- Date: Tue, 9 Nov 2004 13:38:54 +0000
Nisar,
Sorry to be the Bearer of the bad news . But No Where in your Previous
Post did u talk about this .. U were Going way off on RAID and
Parallel Processes and stuff like that ..
Rgds,
Ganesh
On Tue, 9 Nov 2004 05:36:12 -0800 (PST), Nisar Tareen <ntareen@xxxxxxxxx> wrote:
> Ganesh,
>
> Thanks for the note, It do support my view, Please read my note again, I am
> saying the same, I never talk about 1 extent, I emphasis few is better than
> many.
>
> So taking the following note, if you have multiple extent in thousands Oracle
> 9 will also show the strain on resources. Weather there is a technical issue
> on Oracle 8 or Oracle 7 I don't know, but as I had mentioned by reducing
> extent I do get better response. I am not an advocate of cynical 1 extent
> lobby. But for sure few extents are better than 100 and 1000's depending on
> the data and size of each tables.
>
> Regards.
>
> Nisar Tareen
>
>
>
>
> Ganesh Raja <ganesh.raja@xxxxxxxxx> wrote:
> Okay Read this Intresting Post ..
>
> http://www.jlcomp.demon.co.uk/one_extent.html
>
> Guys . Pls Dont Start to Compress to One Extent after u have read this
> Post .. It does not make sense .. Think abt other stuff first ... as
> Jonathan Lewis Says there ... :)
>
> Cheers
> Ganesh
>
> On Mon, 8 Nov 2004 14:53:34 +0000, Ganesh Raja wrote:
> > Nisar,
> >
> > Did not Understand too much from your Post .. But How does all the
> > things that you have talked about affect the way parallelism works ..
> > Parallelism is CPU Bound and not disk bound ... U dictate if you want
> > to Use Parallelism and then The ur Query/DML is Split across multiple
> > processess that works out how to fetch data from the database and
> > processes it.
> >
> > I am disagreeing here with irfhan also when he says that Multiple
> > extents will give u chances of better parallelism. U can write a small
> > testcase with a One Extent Table and See what happens .. U will still
> > get Parallel Reads.
> >
> > The Only thing that has some effect on performance with Multiple
> > Extent is the MBRC value since an Multi Block read cannot be done over
> > multiple extents. [ U will never encounter this has a Problem]
> >
> > Apart from that i will never say that if you have 1000 Extents ur
> > Query is Going to Perform badly and if you have 1 Extent it will
> > perform any better. I need a test case from u to prove that the
> > otherway.
> >
> > Extent has always been a Logical Grouping of Blocks and not a
> > Physicall Grouping.
> >
> > My $0.02 and not my logic ... :)
> >
> > Rgds
> > Ganesh
> >
>
>
> ---------------------------------
>
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