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Archives of the TeradataForum
Message Posted: Wed, 08 Nov 2006 @ 09:53:57 GMT
| Subj: | | Re: Value Ordered NUSI & Regular NUSI on Same Column? |
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| From: | | Victor Sokovin |
| | I don't think there's any advantage to having both a hash and value ordered NUSI on the same column. | |
| | If a query specifies "WHERE date-column = value" then either type of column will allow the indexed access. So what's the reason for having
both? | |
Terry might have his own reasons but the standard idea is that value-ordered indexes should help with *ranges* of dates (or other ranges, for
that matter), i.e., WHERE date-column between value1 and vale2.
I can't comment much on the original question, though, as it is very seldom that one has a chance to extensively experiment with both forms of
indexes (project budget constraints or company's policy on SI in general often prove to be difficult to overcome). For what it might be worth, I
personally think that such experiments are worth carrying out, if time permits. They might yield a relatively expensive solution but it might be
the right solution for those who can implement it.
Regards,
Victor
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