• Subject: RE: Query Optimizer
  • From: "Ken Sims at SWS Nevada" <ken.sws@xxxxxxxxx>
  • Date: Thu, 4 Nov 1999 17:45:46 -0800

Hi Scott -

>Date: Thu, 4 Nov 1999 12:36:07 -0700 
>From: Scott Mildenberger <Smildenber@Washcorp.com>
>Subject: RE: Query Optimizer
>
>I'm not sure why the optimizer chose what it did, one guess might be that
>maybe the access path maintenance wasn't set to *immed so it wasn't current.
>But I do know one thing, if you create a logical file that can reuse an
>existing access path it is built almost immediately.  If the temporary
>access path that the optimizer built exactly matched the existing LF then it
>would have been built in a very short time.  I'm assuming since you asked
>the question that this temporary index took some time to build.  If that is
>the case then there must have been something different between the temporary
>index and the existing LF.  Not sure this helps but you may want to look at
>all the attributes of the existing LF.

The optimizer can be pretty *&%$ stupid at times.  There are situation when
I *know* that a certain logical would work just dandy, but the optimizer
builds a temporary index anyway.  Sometimes I could write, compile, and run
an RPG program to do the same thing in less time than it takes for the index
to build.  :(

The other problem is that the temporary index code is below the normal logical
file creation, so a temporary index will not share an existing logical file
access path.

Ken
Southern Wine and Spirits, Inc.

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