Oppolzer - Informatik / Blog

Hello DB2 list,

we observed the DB2 interface DSNALI consuming 5 percent CPU of a
batch job involving MQ, IMS etc. (measured by Strobe).

Under similar circumstances the DB2 interface for IMS (called DFSLI000)
had a CPU usage of 0,1 percent and below.

We are quite sure that the CPU is indeed used inside the DSNALI CSECT.

Some examination showed that DSNALI dynamically LOADs the modules
DSNACAB and DSNACAF, normally only once. The information, if the
modules are already loaded or still have to be loaded, is stored at some place
in the PSA - at least some PSA location is first read to locate this
information.

My idea is: at our installation, maybe, we do something wrong, so that the LOAD
of these modules is executed on every call, and so this CPU comsumption could
be explained. For example: we don't link the DSNALI interface
via alias DSNHLI to our batch programs. Instead of doing this, we link
a home grown DSNHLI, which examines the environment and then calls
a module (linked RENT, dynamically loaded once), which has DSNALI linked
to it.

I don't yet understand what may be the problem. My next steps will be:
find out, how often the LOAD is executed and if this is really the problem.

Any suggestions?

Kind regards

Bernd