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Are there a lot of logicals over that file? While I havenât seen this myself for a long time, there was a time when the query optimizer would timeout before it go to search a particular access path, so the optimizer would punt (force table scan). I know I saw this prior to SQE...

-Eric DeLong

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Michael_Schutte@xxxxxxxxxxxx
Sent: Monday, July 20, 2009 1:28 PM
To: Midrange Systems Technical Discussion
Subject: SQL Table Scan Concern.


In several web programs, I thought I was being smart by creating tables in QTEMP that would contain selection criteria to query against large data
files because we don't have logicals that met my selection criteria. I
have one that is acting kinda strange. It's not picking a locigal by company and date over the large data file.

The QTEMP Table only has company and date in the file.

i.e.

001 20090601
001 20090602
001 20090604
001 20090605

Notice that one date is missing. The user wants to be able to select
certain days of the week. ie Weekdays only for an entire month. Anyway,
I'm trying join this file to a large data file that does have an index by company and date.

But VisualExplain is telling me that it's doing a table scan over RTA60 because the cost is better. Which I know that isn't true. If I replace RTA60 with the locigal name, it runs as I expect. I hate to use the logical in the query because I also have to give the user the ability to run for select restaurants (so there's another table in qtemp that has the user's selection of restaurants). But nevermind that for now. Just company and date I get horrible response time when listing the physical in
the query. Anybody know why?

select a.*
from sar_dates b
join rta60 a on
a.tcono = b.company and a.tdate = b.dateiso

Does a table scan


select a.*
from sar_dates b
join rta60L9 a on
a.tcono = b.company and a.tdate = b.dateiso

Makes use of the RTA60L9 logical.

Thanks in advance for the help.




--

Michael Schutte
Admin Professional



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