AW: Logical file keyed by active RRN

["HauserSSS" <Hauser@xxxxxxxxxxxxxxx>]

Hi Rob,

your statement will cause the worst performance you ever had.
Because it is not possible to generate an index over the RRN.
The use of the built in function will always cause a table scan (including
all deleted rows!).

SELECT RRN(SHEA), MYFIELD
FROM ROB/SHEA
ORDER BY RRN(SHEA)
....+....1....+....2....+....
       RRN ( SHEA )   MYFIELD
                  1      A
                  3      C
********  End of data  ******

Rob Berendt
--
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





"David C. Shea" <dshea@xxxxxxxxxxxx>
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
07/22/2005 12:55 PM
Please respond to
RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx>


To
<rpg400-l@xxxxxxxxxxxx>
cc

Subject
Logical file keyed by active RRN






I want to create a logical file where the key is RRN.  I only want
active records listed in this logical.



The goal here is to be able to SETLL by key of RRN and have the pointer
positioned either at the next record in the file or EOF.



This is for a situation where there could be millions of deleted records
in the file.  Doing a regular SETLL by RRN and a READ could end up
scanning thru millions of deleted records.



Doing a SETLL on a logical file _keyed_ by RRN might do the trick.



Any thoughts??







--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
list
To post a message email: MIDRANGE-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/midrange-l.


--
This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing list
To post a message email: RPG400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
or email: RPG400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/rpg400-l.


--
This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing list
To post a message email: RPG400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
or email: RPG400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/rpg400-l.