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Message Posted: Sat, 01 Mar 2003 @ 23:16:24 GMT


     
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Subj:   Performance for Distinct values
 
From:   Anomy Anom

<-- Anonymously Posted: Saturday, March 01, 2003 17:38 -->

This question is related to the performance between two different methods. I need to create a Dimension table from a Fact table. I will be loading all distinct values of one column into a table. I expect to get maybe 10 rows into the target table from a source table of 100,000 rows. I have different methods and am considering:

1. Do a GROUP BY or Distinct on the source of a INSERT/SELECT. This of course will require the sorting and redistribution and aggregation (ARSA).

2. Make the target table a SET table, do not use any GROUP BY or DISTINCT on the INSERT/SELECT, and let the Duplicate Row check for the SET table weed out the duplicates.


The question is which method would perform the best.



     
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