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Fwd: RE: separate tablespaces for tables and indexes

From: Peter Barnett <regdba_at_yahoo.com>
Date: Wed, 15 Dec 2004 07:00:30 -0800 (PST)
Message-ID: <20041215150030.21084.qmail@web13422.mail.yahoo.com>


In the bad old days when you had 100+ spindles for a 50G database, separating data files and indexes did matter. If you really want to go back to when this suggestion was originally proposed, spindles were measured in MB. It made sense.

Currently, our storage folks encourage us to treat storage as a 'black box'. Just put your data files wherever it logically makes sense and let the underlying management software take care of the performance issues. That is until they call you and ask you to move some files because they have hot spots on their storage that the managment software cannot seem to load balance.

The point being to understand the underlying 'black box' technology and learn when it matters to manually distribute the data files.

> Subject: RE: separate tablespaces for tables and
> indexes
> Date: Mon, 13 Dec 2004 14:36:48 -0600
> From: "Hollis, Les" <Les.Hollis_at_ps.net>
> To: <davidsharples_at_gmail.com>,
> <oracle-l_at_freelists.org>
>
> >>"i was taught the same thing in 2002 on a dba
> course - until oracle
> stop >>promoting it, myths will never die - but this
> one is pretty
> harmless >>really"
>
>
> Actually, that is STILL taught in DBA Funds I
> course....
>
>
> This is cut from that course Lesson 11 Managing
> Tables
>
>
> "Creating a Table: Guidelines
> Place tables in separate tablespaces, not in the
> tablespace that has
> undo segments, temporary segments, and indexes.
> Place tables in locally managed tablespaces to avoid
> fragmentation."
>
>
> AND from Lesson 12 Managing Indexes
>
> "Creating Indexes: Guidelines
> Consider the following while creating an index:
> Indexes speed up query performance and slow down DML
> operations. Always
> minimize the number of indexes needed on volatile
> tables.
> Place indexes in a separate tablespace, not in a
> tablespace that has
> undo segments, temporary segments, and tables.
> There could be significant performance gain for
> large indexes by
> avoiding redo generation. Consider using the
> NOLOGGING clause for
> creating large indexes.
> Because index entries are smaller compared to the
> rows they index, index
> blocks tend to have more entries per block. For this
> reason, INITRANS
> should generally be higher on indexes than on the
> corresponding tables."
>
>
>
> As of a course I taught this fall at my local
> community college.
>
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of
> David Sharples
> Sent: Monday, December 13, 2004 1:44 PM
> To: oracle-l_at_freelists.org
> Subject: Re: separate tablespaces for tables and
> indexes
>
> i was taught the same thing in 2002 on a dba course
> - until oracle
> stop promoting it, myths will never die - but this
> one is pretty
> harmless really
>
>
> On Mon, 13 Dec 2004 11:39:18 -0800 (PST), Alex
> <stant_98_at_yahoo.com>
> wrote:
> > That is precisely the point I can still remember
> from Oracle
> university classes I took in 1998 on Oracle 8.
> --
> http://www.freelists.org/webpage/oracle-l
> --
> http://www.freelists.org/webpage/oracle-l
>



Pete Barnett
Lead Database Administrator
The Regence Group
pnbarne_at_regence.com                 

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Received on Wed Dec 15 2004 - 09:06:18 CST

Original text of this message

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