Crashing your System i with World Writer

[Eric Lehti]

How World writer can fill up your disk (system auxiliary storage pool) and take down your system hard. Create a query or World Writer to output to a file. Join two or more tables but neglect to join the tables. This will produce a cartesian join. http://www.orafaq.com/wiki/Cartesian_join
joining each row to every row of the other tables.
Your World Writer will merrily create millions of records and fill your disk, producing these messages before your system goes down hard.



Additional Message Information

Message ID . . . . . . : CPF0907
Date sent . . . . . . : 08/07/08 Time sent . . . . . . : 07:23:47

Message . . . . : Serious storage condition may exist. Press HELP.

Cause . . . . . : The amount of available auxiliary storage in the system
auxiliary storage pool has reached the threshold value. This is a
potentially serious system condition. The auxiliary storage capacity is
210,990,268,416 bytes. The auxiliary storage used is 191,498,387,456 bytes. The
threshold is 90.000000 percent. The auxiliary storage available is 9.23828
percent.
Recovery . . . : Use the WRKSYSSTS command to monitor the amount of storag
used. The use of storage can be reduced by the following actions: Save
objects by specifying STG(*FREE); delete any unused objects. Save the old
log versions of QHST that are not currently used and then delete them;
either write or delete spooled files on the system. Failure to reduce the
More..

 

[scott_parker]

Ouch


Scott Parker
Programmer Analyst/Technical Specialist
JDE World 8.1/SalesLogix 6.2/Everything Else they give me
Grote Industries LLC

 

[Eric Lehti]

I have just now begun using QAQQINI to limit the number of seconds that World writers and other SQL jobs can run. See my previous post at:
http://www.jdelist.com/ubb/showthreaded.php?Cat=0&Number=136603

 

[ssolberg]

Re: RE: Crashing your System i with World Writer

As I recall, the WW function that allows you to create a file of the output does a CRTPF (as/400 command) and normally this command has a "default record limit" set. I ran into this because of just the opposite problem. I think the normal default from OS/400 is set to 10,000 records and in my case, I had some users that would occasionally need to make file with more than that. In normal running, the WW report hits that limit and then sits with a Message Waiting on the job until you say it can be bigger or allow you to end the job. We bumped the limit up to 100,000 records so users would not get the message but at the same time a job can't just create a file of *NOMAX size.

So is it possible your CRTPF command has a default set to *NOMAX for file size? Below are some notes I wrote to myself long ago because I think this value gets reset to 10,000 records if you do an OS upgrade.

"World Writer can produce files for downloading and it is a
pain for the CRTPF size default to be 10000 records since
many files will be bigger than this and users do not know
how to answer the question to increase the size.
.
A better approach is to change the defaults on the CRTPF
command to increase the initial size. From the command line
type "CHGCMDDFT CMD(CRTPF) NEWDFT('size(100000 1000 3)')"
and now you won't get the error message until it hits
100,000 records for the max initial size. The other two
parms are # of records for each increment and how many increments"

 

[Eric Lehti]

Re: RE: Crashing your System i with World Writer

Sannon,
Good point you made about the number of records on CRTPF. In our environment we have CRTPF to max out at 275,000 records.