Re: binary radix tree indexes

At 08:51 AM 9/3/98 -0500, you wrote:
>With V4R3 there seems to a significant enhancement with DB2 for OS/400 with
>regards to indexes.  Being fairly ignorant can someone explain to me how
>binary radix tree indexes work (the traditional method)? If I understand
>this I think I can understand the implications of encoded vector indexes
>(EVI) better........than again maybe I can just sound like I understand :-)
>
The Binary Radix Tree index is the standard system index.  There are
actually two forms of this index, those created before CPF Release 7, and
newer ones.  (Yes, those suckers can still be alive!)

The Binary Radix Tree index is a persistent index.  It has enough overhead
(e.g.: weight) that other indexes can share it, and it can last, and be
maintained for years.

An Encoded Vector Index is a significantly smaller index, that is created
for a one-time throw away use by SQL.  Because it doesn't need all that
weight, it's significantly smaller, and is significantly more likely to be
fully contained in memory.

Al




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Al Barsa, Jr. - Account for Midrange-L
Barsa Consulting, LLC.  
400 > 390

Phone:  914-251-9400
Fax:    914-251-9406


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