RE: slow runs

["Elvis Budimlic" <ebudimlic@xxxxxxxxxxxxxxxxxxxxxxxxx>]

With good journaling strategy you should only incur around 4% overhead.  It
does depend on the environment, so your mileage will vary.
I have not heard of using journaling as a performance improvement tool, but
I suppose it is possible if talking about turning on concurrent write
support.

To view CFINT activity, I usually utilize WRKSYSACT command.

Elvis

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of murali dhar
Sent: Monday, January 24, 2005 10:28 AM
To: Midrange Systems Technical Discussion
Subject: RE: slow runs

Does commitment control and journalling is going to increase job-speed?
At the moment no journalling is in the library where slow run was reported.
We are planning to enable  the caching on memory pool.We are on V5R3.
how do i find an interrupt CFINTxx(which slows down everything) is there on
our model of iseries?

rob@xxxxxxxxx wrote:
Well, that wasn't exactly what I wanted to hear. I was hoping to hear 
that I didn't have to do 'x' to get journalling to perform as well as not 
journalling. I was hoping to hear that just journalling increased speed, 
failing that, not that it degraded it.

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





"DeLong, Eric" 
Sent by: midrange-l-bounces@xxxxxxxxxxxx
01/21/2005 03:09 PM
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RE: slow runs






I think it allows for asynchronous writes, but I can't remember what was
special about it.... Oh yeah! I found it in my saved tips folder...


From: Vern Hamberg [vhamberg@xxxxxxxxxxxxxxxxxxxxxxxxx]
Sent: Thursday, May 01, 2003 9:48 AM
To: Midrange Systems Technical Discussion
Subject: Re: Journal performance problems

There's a little-known solution - turn on commitment control. Without 
this, 
jobs can take 3-4 times as long to finish. Here's an extract from an 
article by Rick Turner:

Commitment Control & Journaling
Though most database and other write operations are asynchronous, database 

journal receiver write operations are usually synchronous to the issuing 
job. This means the job is forced to wait (in the system's disk I/O write 
functions) for the I/O (write) to complete before it continues processing. 

The SLIC Journal functions can do the journal writes asynchronously if the 

job uses commitment control.
When commitment control is in effect, the database journal write functions 

know that file integrity is required only at a commit boundary and not at 
every record update/add/delete operation. Because of this, the database 
journal writes are scheduled asynchronously. When a commit boundary is 
reached, the database functions ensure that all pending database file I/O 
is complete before continuing.
Lab tests show that using commitment control and journaling yields 
performance almost equal to not using database journaling. If you use 
journaling but not commitment control, a job can be three to four times 
slower than when you don't use journaling at all.
"But this means I have to change my code!" you say. True, but the cost of 
the changes are minimal compared to the performance benefit. In the CL 
program that calls the batch program, specify the files that use 
commitment 
control and open them. Start a commit cycle in the CL program before 
calling the batch program. In the application program(s), change the file 
description to specify that commitment control is in use. Once the program 

returns to the CL program, end the commit cycle to force any pending file 
I/O to complete.

There's more in the article, including side effects of SMAPP on journaling 

performance, available at
<
http://www-1.ibm.com/support/docview.wss?uid=nas1e907e76673a614dd86256a2900

54f546&rs=110>

HTH

Vern


Eric DeLong
Sally Beauty Company
MIS-Project Manager (BSG)
940-898-7863 or ext. 1863



-----Original Message-----
From: rob@xxxxxxxxx [mailto:rob@xxxxxxxxx]
Sent: Friday, January 21, 2005 12:26 PM
To: Midrange Systems Technical Discussion
Subject: RE: slow runs


Sounds familiar...

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





"Ingvaldson, Scott" 
Sent by: midrange-l-bounces@xxxxxxxxxxxx
01/21/2005 12:02 PM
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RE: slow runs






Doesn't journalling automagically enable concurrent writes, or something 
like that?

Regards,

Scott Ingvaldson
iSeries System Administrator
GuideOne Insurance Group

-----Original Message-----
date: Fri, 21 Jan 2005 11:20:50 -0500
from: rob@xxxxxxxxx
subject: Re:slow runs

I've heard that journalling can make things run faster. I forget why.

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





"Muralidhar Narayana" 
Sent by: midrange-l-bounces@xxxxxxxxxxxx
01/21/2005 11:05 AM
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Re:slow runs




Nothing else in running at same time , Iam doing testing, I have stopped 
others jobs.

Iam tryiung to find out how this could make difference and what are the 
factors that are going to influence?

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