Re: Indexes vs Logical Files

It probably is using one of the existing LFs...

But by default, the page size of an LF is much smaller than what is used by
default for an index.
Additionally, with only a subset of the key's that are in the existing LFs,
the suggested index would store more data per page.

Basically, the optimizer thinks such an index would be helpful.

The only way to know for sure is to create it and try it out.

Charles



On Fri, Oct 13, 2023 at 6:48 AM Greg Wilburn <
gwilburn@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

I've been using Index Advisor and Run Sql Scripts "Run and Explain" to
analyze some of our queries. I'm looking for increased performance.

I have a large file/table OEBOXCBX with a logical files defined with the
following keys:

LF #1: BXCOM#, BXORD#, BXREL#, BXBOX#, BXPRT#
LF #2: BXCOM#, BXORD#, BXREL#, BXBXNO, BXPRT#

I ran an SQL statement over a complex SQL view that contains this file.
RSS Run and Explain recommended the following index:
CREATE INDEX ASTHHOBJ/OEBOXCBX_IDX
ON ASTHHOBJ/OEBOXCBX (BXCOM# ASC, BXORD# ASC, BXREL# ASC) UNIT ANY
KEEP IN MEMORY NO;

My question is why the SQE wouldn't use one of the existing logical files
as an index? As an RPG guy, this makes no sense to me.

TIA,
Greg

[Logo]<https://www.totalbizfulfillment.com/> Greg Wilburn
Director of IT
301.895.3792 ext. 1231
301.895.3895 direct
gwilburn@xxxxxxxxxxxxxxxxxxxxxxx<mailto:gwilburn@xxxxxxxxxxxxxxxxxxxxxxx>
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Grantsville, MD 21536
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