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I may be wrong, but I seem to recollect hat Query will never use existing access path - unless you point it directly to LF. Best regards Alexei Pytel Joel Fritz <JFritz@sharperimage.com> on 11/19/99 10:45:11 AM Please respond to MIDRANGE-L@midrange.com To: "'MIDRANGE-L@midrange.com'" <MIDRANGE-L@midrange.com> cc: Subject: RE: SQL Cursor Questions(and query 400) Does this apply to Query400? I know I've improved the batch performance of queries dramatically by pointing them at an existing logical file when they built an access path when pointed at an unkeyed physical. > -----Original Message----- > From: pytel@us.ibm.com [mailto:pytel@us.ibm.com] > Sent: Thursday, November 18, 1999 6:25 PM > To: MIDRANGE-L@midrange.com > Subject: Re: SQL Cursor Questions > > > > > /* SNIP */ > > SQL does not care, whether you address PF or LF - it will always use > underlying data in the way it considers is most optimal. > The difference between SQL in interactive session and SQL > imbedded in a > program is that optimization goals are slightly different. > By defaut, interactive SQL is biased to returning first > screenful of data > as fast as possible, and imbedded SQL is geared to reduce > entire processing > time. This will explain why access path was used for > interactive and not > for batch - arrival access path may be more efficient if > large subset of > file records is selected. > > > Best regards > Alexei Pytel > > > > +--- | This is the Midrange System Mailing List! | To submit a new message, send your mail to MIDRANGE-L@midrange.com. | To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com. | To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com. | Questions should be directed to the list owner/operator: david@midrange.com +--- +--- | This is the Midrange System Mailing List! | To submit a new message, send your mail to MIDRANGE-L@midrange.com. | To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com. | To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com. | Questions should be directed to the list owner/operator: david@midrange.com +---
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