[askdba] Re: Need help with Interview Questions
- From: "Subodh Deshpande" <subodh_deshpande@xxxxxxxxx>
- To: askdba@xxxxxxxxxxxxx
- Date: Tue, 09 Nov 2004 01:41:25 -0500
hello rajesh, irfan, ganesh, nisar
you have nicely explained your thoughts..
and please read peplings posting once again..
and read the contents of the urls posted by you..you will find the similari=
ties in his answer and the writers of the urls posted by you..
i will say in short if both are used correctly for the right objects then o=
nly they are beneficial, the size of the extents and allocation policy de=
pends on application logic, business process flow and how it is finally con=
verted into a database design and application design..
rajesh, this question was one of the important question of your interview, =
the interviwer was really intelellegent and experienced..there were many qu=
estions in his single question
he did tested your domain knowledge
he did tested what features you have used from oracle database technology
have you correctly used the features of oracle for that domain
how you have used them (method of using them and your dba skill)
while using how you look at it and finally what will the effect of that tha=
t..
in all this discussion, can you think/feel that table can be created by rec=
overying a database also..
i think he was giving you hint by asking the question about recovery...
thanx in advance..subodh
----- Original Message -----
From: "Irfan Khan" <irfan.khan@xxxxxxxxxxxx>
To: <askdba@xxxxxxxxxxxxx>
Subject: [askdba] Re: Need help with Interview Questions
Date: Mon, 8 Nov 2004 17:29:04 -0500
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> Forgot the link in last email
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> http://www.kevinloney.com/free/extperf.doc
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> Regards
> Irfan Khan
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> -----Original Message-----
> From: Nisar Tareen [mailto:ntareen@xxxxxxxxx]
> Sent: Tuesday, November 09, 2004 5:42 AM
> To: askdba@xxxxxxxxxxxxx
> Cc: dba Group
> Subject: [askdba] Re: Need help with Interview Questions
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> Ganesh,=3D20
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> =3D20
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> I did not recall of mentioning Parallelism what I rote to Irfan, My =3D
> answer was about multiple extents.=3D20
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> =3D20
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> Yes, I will stand on my ground that multiple extents (as I said extra =3D
> ordinary) will affect the performance for full table scan, as the disk =
=3D
> head had to reposition itself
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> To make extra hits (I/O) for read and write/update, and extra block =3D
> addresses in SGA for the records read.
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> =3D20
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> My understanding my logic, Ganesh most of the time I write from the top =
=3D
> of my mind, After doing this work for so long, I do not go through the =
=3D
> technical manual, My idea is not to write technical manual for every =3D
> email or query, Email should give the major guide line on the issue and =
=3D
> each one of us the user should go the extra 9 yards according to our =3D
> needs. =3D20
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> =3D20
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> Believe me I ran Tara byte database and I don't have to prove, I had =3D
> done my proving, Few extents are better that many.=3D20
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> =3D20
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> I am not an academic and I am running a shop and the time I have I enjoy =
=3D
> answering emails and some time for fun add my logic. But Oracle is in =
=3D
> the business of proving yes I can be wrong then you just have to say, =3D
> Nisar here you are wrong. I will and you can give the understanding on =
=3D
> an issue, its okay with me.=3D20
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> =3D20
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> Plus, extents are Physical blocks not logical. eg. 1 block of 10 giga =
=3D
> bytes or 10 blocks of 1 biga bytes.=3D20
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> =3D20
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> Have Fun.=3D20
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> =3D20
> Nisar Tareen=3D20
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> Ganesh Raja <ganesh.raja@xxxxxxxxx> wrote:
> Nisar,
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> 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.
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> 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.
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> 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]
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> 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.
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> Extent has always been a Logical Grouping of Blocks and not a
> Physicall Grouping.
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> My $0.02 and not my logic ... :)
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> Rgds
> Ganesh
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> =3D09
> ---------------------------------
> Do you Yahoo!?
> Check out the new Yahoo! Front Page. www.yahoo.com
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>=20
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Good Luck..Subodh Deshpande
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Experience Is Knowledge
Wisdom Is Philosophy
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--=20
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