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Re: db block Size for Indexes Tablespaces in 9.2 ?

From: Arup Nanda <arupnanda_at_hotmail.com>
Date: Tue, 17 Dec 2002 10:44:14 -0800
Message-ID: <F001.0051B83D.20021217104414@fatcity.com>


I can't point to a paper or article on that, but based on tests I have done, the block size of index tablespaces for a high volume transaction system should be lower than the table block sizes. 2000 tps with 25 changes each does not sound like a really huge transaction rate. You could set the tables' block size as 8k and indexes' as 4k.

The reason for smaller block sizes in index is simple - to reduce the dreaded buffer busy waits that will inevitably happen for this type of transaction rate. A smaller block size will make sure less number of rows are in a block - making the chance that two sessions are trying to get the same buffer low.

Caveat - if your database has a large percentage of DSS type quries (you mentioned hybrid), then they will suffer slightly as the block gets will increase.

HTH Arup Nanda

>
> What is the Best Practice for DB_BLOCK_SIZE for Index Tablespaces
Undergoing High Volume of Insert , Update , Selects ? Why ?
>
> Any Docs , Links for the Same ?
>
>
> NOTE - This is for a Hybrid Application Benchmark undergoing 2000 Banking
Transactions per second
> approx.
>
> OLTP Transaction sample = 1 Cash Deposit Transaction undergoing Insert
Update Delete Operations on Total of 5 Tables Each having About 5 Indexes
>
> Thanks
>
>
>
> --
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> --
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> INET: VIVEK_SHARMA_at_infosys.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Arup Nanda
  INET: arupnanda_at_hotmail.com

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Received on Tue Dec 17 2002 - 12:44:14 CST

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