Logical I/O results from same data(Index/table) being accessed multiple times from the memory ie. the data that was fetched earlier and remains in the Bufferpool and when it is requested again it is retrieved from the BP or memory(ie. it is a memory I/O and obviosuly is preferred over Physical I/O )

Some of the strategies which you can implement to reduce Logical I/O are (This by no means is the is the complete !)

1. Caching the result set at the application level.
2. Designing better indexes
3. Clustering the data on indexes. Clustering is nothing but grouping of data in data pages based on a particular indexes order/sequence.
You may read this doc to improve your understaning about clustering , covering index design etc.

http://www-128.ibm.com/developerworks/db2/library/techarticle/0303kuznetsov/0303kuznetsov.htmlding




-----Original Message-----
From: sonika
[mailto:db2udbdba-ezmlmshield-x338828.[Email address protected]
Sent: 28 July 2005 10:46
To: LazyDBA Discussion
Subject: How to reduce Logical I/O




Hi Great DBA's



Please tell me how can I reduce Logical I/O



The role of arraysize & clustering factor



Thanks & Regards



Sonika Choudhary



Times Internet Limited.

MPD Tower, Sector Road Zone-VI,

DLF Phase-V,Opp DLF Golf Course,

Gurgaon-122002,Haryana

Tel. No.-0124-5187000/100/200,Extn-2355

Mobil-9891378817.





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