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From "Martin, Layla (HP DualStudy)" <layla.mar...@hp.com>
Subject Index Type
Date Thu, 06 Aug 2015 07:25:58 GMT
Hi,

Sorry for just another question ...

I got another question regarding Trafodion indexes. Which type of index do you use?

I conducted a test with 50000 table rows and a varying frequency (number of different entries
in the indexed column).

This test has shown the best results (best benefit over not using an index) for frequencies
100 and 1000 (I've tested 1, 5, 50, 100, 1000, 10000 and 50000, the optimizer didn't use the
index for 1 and 5).
I thought that B-Trees work best with a frequency close to log(number of rows), but the results
have been best close to sqrt(number of rows).

Do you have an explanation for that?
I didn't find any information on that in the docu/wiki or on Git.

Best regards
Layla

Layla Martin
HP DualStudy
Hewlett-Packard GmbH
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