Show us the relent dictionary items, the SQL statement, and the "LIST.INDEX
{filename} ALL" output
You should also try native SELECT commands using the index to see if
performance is as expected.
SELECT ... FROM CUSTOMER WHERE I_ZIP = "12345"; vs
LIST CUSTOMER WITH I_ZIP = "12345"
Also, try including "REQUIRE.INDEX" and then "NO.INDEX" at the back end of your
command to see the difference.
The 'REQUIRE.INDEX' will fail if the selected index could not be used:
REQUIRE.INDEX
________________________________________________________________
Use in a RetrieVe command to specify that secondary key
indexes must be used to process the sentence. If indexes
cannot be used, an error message appears and the sentence does
not proceed.
The 'NO.INDEX' will bypass the use of an index, showing the resulting
performance change:
NO.INDEX
_________________________________________________________________
Use in a RetrieVe command to specify that secondary key
indexes not be used if they exist. This is useful when indexes
are not up to date or built.
Finally, the order of occurrence of the selection criteria can impact the use
of secondary indices.
... david ...
David L. Wasylenko
President, Pick Professionals, Inc
w) 314 558 1482
d...@pickpro.com
-----Original Message-----
From: u2-users-boun...@listserver.u2ug.org
[mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Allen Egerton
Sent: Friday, July 27, 2012 10:35 AM
To: .U2 List
Subject: [U2] Universe; SQL; Indexes?? (10.3.7 on Windows)
I'm using SQL to query Universe 10.3.7 data files, (ANSi-compliant and
non-compliant formats) and indexing the files to try to optimize the
performance seems in some cases to have little or no effect.
I'm pretty clear on index behavior with Universe's native query language, but
SQL is somewhat unfamiliar to me, and I'm wondering why I'm not getting the
behavior I expect.
Can anyone either point me to reference material on this, or offer thoughts
based on experience?
Thank you.
--
Allen Egerton; aeger...@pobox.com
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