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Message Posted: Tue, 28 Feb 2006 @ 18:41:58 GMT


     
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Subj:   Re: Performance problem with View Layering
 
From:   Michael Larkins

The first thing that I notice is that your join columns can have different domains (VARCHAR(30) and CHAR(10)). So, you are using SPOOL and JOIN logic to get rid of any value longer than 10. Plus, you are using TRIM on a VARCHAR column and wasting CPU to accomplish absolutely nothing. So, my first two suggestions would be:

1. add: WHERE CHAR(B.DATA_SOURCE_CD) > 10 /* since DATA_SOURCE_CD in the account_event table is CHAR(10) */

2. change ON: > ON COALESCE(TGT.DATA_SOURCE_CD),'') = COALESCE(B.DATA_SOURCE_CD,'' ) /* no sense trimming both */

Furthermore, is it possible to actually have a ' ' in the data? If so, you might want to use a word like 'null' in your coalesce to distinguish between a real space and a null.


Just a thought.

Michael Larkins
Certified Teradata Master
Certified Teradata SQL Instructor



     
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