Re: Index Selection

Wow...work management changes cause the query to re-optimize? I guess that
makes sense...memory and all. Hmmm...I'll check that out.


On Fri, Aug 9, 2013 at 3:07 PM, Jim Oberholtzer <midrangel@xxxxxxxxxxxxxxxxx

wrote:

Same work management set up? (subsystem, memory, routing entry, etc)
Those things can affect some of the decisions made.

More recently with systems that are doing more and more SQL, I have been
turning off the automatic tuning feature of IBM i, since every time it
makes and adjustment to memory or activity level the query needs to
re-optimize. Leaving memory and activity levels alone, optimizes the
optimizer to be slightly obtuse about it.


Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects

On 8/9/13 1:56 PM, Michael Ryan wrote:

Ok...two systems, both on 7.1. Execute STRDBG UPDPROD(*YES). Run a

program

on system A. Job log shows an index was used for bit map processing. Run
the same program on system B. Same index in place (though different
libraries). System B job log says arrival sequence was used. How can I
figure out why the index is used on one system and not the other? Thanks!
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