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Archives of the TeradataForum
Message Posted: Wed, 17 Nov 2010 @ 20:09:53 GMT
| Subj: | | Re: Teradata's Indexing: PPI vs PI |
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| From: | | Faible Mou |
frank.c.martinez wrote:
| | Primary indexes are not b-trees. They're hashed access. Since Primary Indexes are just hashed keys, and "Unique Primary Indexes (UPIs)
guarantee uniform distribution of table rows." | |
Hi,
I'd like to know more about Primary Indexes, if it not a trade secret.
I meant, how can this guarantee be possible? Hashing is bound to have collides. Even 128b md5 can't avoid it. How big is TD Index to avoid hash
collides? Is its hashing result better (more uniformly distributed) than md5? How is it's hashing speed comparing to computing md5?
Thanks
FM
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