Re: Index advisor advising index on primary key

[Jeff Crosby <jlcrosby@xxxxxxxxxxxxxxxx>]

There is a view that joins this table with another table of "old" item 
numbers (OLITMMST).  This table's name is DMITMMST.  That view was 
created like this:

CREATE VIEW ALITMMST AS (
  SELECT A.*,CAST(00010101 AS NUMERIC(8,0)) AS DLDAT FROM DMITMMST A
  UNION ALL
  SELECT B.* FROM OLITMMST B )                                    

As you can see, OLITMMST has 1 additional field, the deleted date.  I do 
not use ALITMMST anywhere in production RPG, the buyers use that view 
for querying.

The file is not used in any WITH AS, but it is definitely used in SELECTS.

Vernon Hamberg wrote:
> Hi Jeff
>
> Is this table used in any nested view situations? Like a WITH AS 
> (correlated table expression) or as the file in a SELECT (nested 
> table expression)? Or is there a view defined over it that you 
> further use in some indirect way? In the past I have seen where an 
> index is being created over a temporary table - and this can cause 
> the advice. I was told at COMMON that this should not happen, but I 
> suggest calling IBM with lots of information about the use. Does the 
> index advice tell you which statement caused the advice?
>
> HTH
> Vern
>
> At 07:42 AM 4/11/2008, you wrote:
>
>   
> >    Yes, It's DDL defined and yes, the suggested index is the exact primary
> >    key, ITNBR.  That's the one and only primary key field.  Weird, huh?
> >
> >    Wilt, Charles wrote:
> >
> >  Jeff,
> >
> >  IIRC, this will sometimes happen with a DDS defined file because 
> > an SQL index has more statistical
> >  information that the query engine can use.
> >
> >  But you say your file is a DDL defined table....so I don't know....
> >
> >  Is the suggested index the exact primary key?  How many fields in the PK?
> >
> >  Charles Wilt
> >  Software Engineer
> >  CINTAS Corporation - IT 92B
> >  513.701.1307
> >
> >  wiltc@xxxxxxxxxx
> >
> >
> >
> >
> >  -----Original Message-----
> >  From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-
> >  bounces@xxxxxxxxxxxx] On Behalf Of Jeff Crosby
> >  Sent: Friday, April 11, 2008 8:30 AM
> >  To: Midrange Systems Technical Discussion
> >  Subject: Index advisor advising index on primary key
> >
> >  At our LUG meeting earlier this week a fellow midranger (Thanks Rob!)
> >  gave a presentation on things you might not have known about on the i.
> >  One of them was iNav index advisor, which I did not know about.
> >
> >  I cleaned out the advice since much of it was old so it would start fresh.
> >
> >  On our item master file, it is advising that I create an index on field
> >  ITNBR.  This file is an SQL table created via DDL (not DDS) and ITNBR is
> >  the primary key.  Does this advice make sense?  Why would it advise an
> >  index on the primary key?
> >
> >  Thanks.
> >
> >  --
> >  Jeff Crosby
> >  UniPro Foodservice/Dilgard
> >  260-422-7531
> >  Opinions expressed are my own and not necessarily those of my company.
> >  Unless I say so.
> >
> >
> >  --
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> >  --
> >  Jeff Crosby
> >  UniPro Foodservice/Dilgard
> >  260-422-7531
> >  Opinions expressed are my own and not necessarily those of my 
> > company.  Unless I say so.
> > --
> > This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
> > To post a message email: MIDRANGE-L@xxxxxxxxxxxx
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