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Archives of the TeradataForum
Message Posted: Mon, 04 Nov 2002 @ 17:43:34 GMT
Subj: | | Re: Secondary Indexes on an Active Data Warehouse |
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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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