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Message Posted: Mon, 05 May 2008 @ 20:32:35 GMT

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Rahul:

The only way to reduce I/O is to read fewer blocks. There are a couple of potential ways to do this:

1. Index usage

a. Primary columns in WHERE

b. Secondary columns in WHERE

c. NUSI covers (all columns needed) the query

2. larger block size = more rows in block = fewer blocks and the system always does block reads

3. Partitioned Primary Index

Hope this gives you some ideas,

Michael Larkins
Certified Teradata Master
Certified Teradata SQL Instructor

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