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Archives of the TeradataForum
Message Posted: Mon, 15 Mar 2004 @ 17:27:16 GMT
| Subj: | | Re: Odd explain plan in a query using MINUS |
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| From: | | David Wellman |
John,
I've seen the same things with UNION. (I think) What's happening is that Teradata is hashing the entire row and distributing based on that
hash, then looking within the set of rows with same rowhash for duplicates in order to do the MINUS function. "It ain't pretty" and it could be
done another way, but I think you'll find that is what is happening.
Cheers,
Dave
Ward Analytics Ltd: Information in motion ( www.ward-analytics.com )
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