Re: Query Optimizer

If you have many similarly keyed large logicals and a short query time limit and
your best logical is older than the rest - than it could time out before
selection.

Dan Jahr







Pete Hall <pbhall@execpc.com> on 11/03/99 07:11:42 PM

Please respond to MIDRANGE-L@midrange.com
                                                                                
                                                                                
                                                                                


                                                              
                                                              
                                                              
 To:      MIDRANGE-L@midrange.com                             
                                                              
 cc:      (bcc: Danny Jahr/Lawson)                            
                                                              
                                                              
                                                              
 Subject: Query Optimizer                                     
                                                              







Does anyone have a clue as to why the query optimizer would chose to build
a temporary access path with a key that exactly matches the second of two
logical files (no includes or omits)? The explanation says that "The cost
to use this access path, as determined by the optimizer, was higher than
the cost associated with the chosen access method" (which was to build a
temporary index). Does the fact that this is a logical file (DDS) as
opposed to and SQL index have any bearing on the matter? This is at V4R3,
current on database PTFs.
Pete Hall
pbhall@execpc.com
http://www.execpc.com/~pbhall
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