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Message Posted: Wed, 05 Dec 2012 @ 15:23:47 GMT

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Hi Sughesh,

As with a lot of things in Teradata, the answer about "what will happen" is not always a simple one.

"But if you defined only PI, TD will always do duplicate row check with all rows present in table. So there will be considerable degradation."

Teradata will not " do duplicate row check " if there is no unique index present and IF the table is defined as Multiset. It will only do the duplicate row check IF the table is defined as SET.

If there is a duplicate row check it is typically not " with all rows present in table ". The only rows that are checked are other rows which have the same row hash as the one being inserted or updated. Yes, I accept that may be 'all the rows' but that is not the typical case.

There was a thread on this forum recently, this links into one of the posts towards the end of that thread. Hope it helps.

www.teradataforum.com/teradata/20120723_170844.htm

Cheers,

Dave

Ward Analytics Ltd - Information in motion (www.ward-analytics.com)

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