Re: Behavior of indexes after run a CLRPFM

["Mark Murphy/STAR BASE Consulting Inc." <mmurphy@xxxxxxxxxxxxxxx>]

How about visual explain feature in IBM i Navigator?

Mark Murphy
STAR BASE Consulting, Inc.
mmurphy@xxxxxxxxxxxxxxx



From:   Rui Feliz <rmfeliz@xxxxxxxxx>
To:     Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Date:   01/20/2011 11:23 AM
Subject:        Re: Behavior of indexes after run a CLRPFM
Sent by:        midrange-l-bounces@xxxxxxxxxxxx



Hi.

Im working on AS/400. The only tool I know is PRTSQLINF. Anybody knows
another?
It's very strange, the index looks ok, but the optimizer don't uses it. In
this situation, I drop the index and I create it again. After this, the
index is used by the process.
The only clue I have that perhaps causes problems is the CLRPFM  that I 
run
in the beginnig of the process. The CLRPFM cleans the statistics of the
indexes?
Rui


On Thu, Jan 20, 2011 at 2:42 PM, <rob@xxxxxxxxx> wrote:

> I think there is an explain tool available in iNav which may help.  It 
may
> decide that it was more economical to do a full table scan or some such
> thing.  For example, if you did a CLRPFM and inserted one row, why 
bother
> with an index?
>
>
> Rob Berendt
> --
> Group Dekko
> Dept 1600
> Mail to:  2505 Dekko Drive
>          Garrett, IN 46738
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>
>
>
>
>
> From:   Rui <rmfeliz@xxxxxxxxx>
> To:     midrange-l@xxxxxxxxxxxx
> Date:   01/20/2011 09:22 AM
> Subject:        Behavior of indexes after run a CLRPFM
> Sent by:        midrange-l-bounces@xxxxxxxxxxxx
>
>
>
>
> Hello.
>
> Sometimes, when I run some SQL operations (like a select), the SQL
> Optimizer
> does not use the correct index.
> Before I load the table, I run a CLRPFM over it.
> Can the CLRPFM be responsable for the non-use of the indexes? The RGZPFM
> fix it?
>
> Best Regards,
>
> Rui
>
>
>
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