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Message Posted: Mon, 04 Nov 2002 @ 17:43:34 GMT


     
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Subj:   Re: Secondary Indexes on an Active Data Warehouse
 
From:   Tressler, Dara C.

I have tested secondary indices with Multiload and with BTEQ. Both show the same significant performance degradation with secondary indices on. It is a necessity to drop the indices before the load and then reindex. This takes much less time than having the indices present with BTEQ or with Multiload. It did not seem to matter what the indices were (most secondary indices seem to be skewed one way or another because they do not uniquely identify one line). I might mention that the optimizer for accessing the table creates queries that are much faster with secondary indices on (with statistics collected) then without them. Also, some tools, like MSI, require the indices to operate efficiently.



     
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