RE: a need for speed

One more thing to consider.  If this is a one off report, the easiest to
code approach is probably the best unless performance is abysmal.  If
it's a regular production job it kind of depends on how long both take.
If the run time is in hours it's probably worth optimizing it.  If it's
in minutes both ways it depends on how frequently it's run and whether
users are waiting with bated breath.

I wish I could remember the break even point between random and
sequential I/O, but I know it's completely counter intuitive. 

<><><>-----Original Message-----
<><><>From: rpg400-l-bounces@xxxxxxxxxxxx
<><><>[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Tom Liotta
<><><>Sent: Thursday, August 18, 2005 5:04 PM
<><><>To: rpg400-l@xxxxxxxxxxxx
<><><>Subject: RE: a need for speed
<><><>
<><><>AFAIK, Booth's method would "work", but Scott's _could_
<><><>easily be faster. The ordering would be the same for both
<><><>and grouping would be defined the same. Scott
<><><>positions-to and READs the first and last record in every
<><><>group giving lowest and highest suffix (as long as
<><><>ordering and grouping are correct) in the group. Booth's
<><><>method would give the lowest suffix at L1-Detail time and
<><><>the highest at L1-Total time.
<><><>
<><><>However, Scott has a point when the average number of
<><><>records in groups exceeds some number. If records are
<><><>1000 bytes in size and groups average say 50000 records,
<><><>then maybe it's not such a good idea to read individual
<><><>records. But if groups average 5 records, then it hardly
<><><>matters whether records are all read or not -- most will
<><><>be physically read anyway and there'll be no READPs nor
<><><>any other complicating code paths internally.
<><><>
<><><>Tom Liotta
<><><>
<><><>rpg400-l-request@xxxxxxxxxxxx wrote:

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