RE: Improving SQL Update perfomance

SETOBJACC - have not heard it is a NOOP - You certainly receive messages telling you how much has been allocated and all that. There is also a SETACST MI function that does the same, and more.

Expert Cache - *FIXED and *CALC are what you say in WRKSYSSTS or WRKSHRPOOL - only shared pools can have these set in these interfaces. You CAN change even the paging characteristics of private pools - using a Change pool attributes API. Dangerous waters - be careful!

Vern

-------------- Original message ----------------------
From: "DeLong, Eric" <EDeLong@xxxxxxxxxxxxxxx>

I'd be surprised to hear that.... Perhaps you're thinking of Expert Cache,
which manages storage pool paging (*CALC in the stoarge pool paging option).....
Here's an article I found:

http://www.itjungle.com/fhg/fhg121306-story03.html

Eric

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx]On Behalf Of Walden H. Leverich
Sent: Wednesday, November 28, 2007 4:15 PM
To: Midrange Systems Technical Discussion
Subject: RE: Improving SQL Update perfomance


I recall hearing somewhere (from an IBMer?) that SETOBJACC is
effectively a No-Op these days. That is to say, you can call it (so
existing code doesn't go boom) but it doesn't do anything. IIRC, this
was V5R2-ish time.

Then again, I could be smoking dope.

-Walden
--
Walden H Leverich III
Tech Software
(516) 627-3800 x3051
WaldenL@xxxxxxxxxxxxxxx
http://www.TechSoftInc.com

Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Elvis Budimlic
Sent: Wednesday, November 28, 2007 4:08 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: Improving SQL Update perfomance

If you have lots of main memory consider using SETOBJACC command to
prebring
the entire file into memory prior to running the UPDATE.

Elvis

Celebrating 10-Years of SQL Performance Excellence on IBM i5/OS and
OS/400
www.centerfieldtechnology.com

-----Original Message-----
Subject: Improving SQL Update perfomance

Hi list,

What would be the best way to improve the performance of
a SQL Update statement executed with RUNSQLSTM?

I need to run the following SQL for several tables:

UPDATE LIBNAME/TABLE SET
Field1 = round(field1 / 1000, 2),
Field2 = round(field2 / 1000, 2),
...
Fieldn = round(fieldn / 1000, 2);

Each one of these tables can have several thousands of
records. One of them has 15 million of records, and the
process is VERY slow.

Thanks in advance,

Luis