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Hi, Mike:

Jobs do not get "swapped out" in i5/OS or OS/400 (any more). There is no such thing as "swapping" in i5/OS. There used to be something called the Process Access Group (PAG), but as of at least V5R2 and perhaps earlier, the PAG is always empty. At V6R1, there is no PAG.

From the* V6R1 _Memo To Users_* manual:

*MATPRATR MI instruction
*i5/OS no longer provides an access group when initiating a process.
The Materialize Process Attributes (MATPRATR) MI instruction now
returns a null pointer for the process access group. Any customer
program that uses the MATPRATR MI instruction and depends on
receiving a non-null pointer will need to be changed.


OS/400 is purely a paging system, so the longer a job remains in a wait state, the more chances for other jobs to "steal" the real page frames of pages that were formerly occupied by stuff pertaining to that job. So, in effect, you could "say" the job was "swapped out" because, the longer it waits, the more pages can get "stolen" and so the longer it might take to demand-page them all back in again, in order for the job to continue executing.

Hope that helps ...

Mark S. Waterbury

> Mike Krebs wrote:
How would
you know for sure that a job got swapped out to disk? Is this information
recorded somewhere?

I'm not technical enough to dig into the bowels, and put an exact status on
something. But you can see Elapsed AuxIO on the WRKACTJOB screen (F11). This
includes database and non-database paging. It gives you an idea that
something might need to be looked at. But, since a lot of AS400 jobs have
heavy IO it probably isn't the level of detail you are looking for.


I'm thinking of a program that we
have that uses an SQL request that functions normally then suddenly takes a
long time to execute.


SQL has some cool internal features. One is the use of temporary indexes.
These indexes speed up SQL tremendously when they exist, but can take a
while to be created. With SQL, it is important to make sure you have good
indexes across your tables and get rid of the things which cause it to use
slower methods (logicals with select/omit for example). Subscribe to the
Centerfield Technology newsletter. You will pick up some good SQL knowledge.

Performance (especially job level) is a specialized area. The perfomance
tools and associated reports will help you identify what you are looking
for. Also, there is a section on performance in the infocenter. Many
references there.

Mike Krebs

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