[C400-L] Optimization question

["Eugene Astanovsky" <j.astanovski@xxxxxxxxxxxx>]

Can someone give me an advise on hour to achieve maximum perfomance in  the
following case.

I have a program, that is actually an API, called from PC via Client Access.
This program is "seen" in WRKACTJOB under WRKSYS/QZRCSRVS. Program is called
frequently and I have to maximize its speed.
For its operation it requires a temporary PF, which is created in QTEMP by
the program.
What I do now in my C program is :
CRTDUPOBJ OBJ(HZY041) FROMLIB(KFILEEK) TOLIB(QTEMP) OBJTYPE(*FILE)
Program fills file with data, then sends data away, clearing this file as
data is transferred.
When program ends it's job, file is empty, as I delete each record after
sending it.

I looked at the job log, and each time it says :

Object HZY041 in QTEMP type *FILE already exists.

Now as performance is a bottleneck, I have several choices.
1. Leave it as is and find for a solutions somewhere else - I do not know if
this is a performance issue :-(
2. Delete file as soon as it is empty - then I probably will not get this
error message, but will have to create it for each call.
3. Check, if file exist before creating it and make CRTDUPOBJ only if the
file does not exist.

My question is which of the choices is the best? And if the best is nr.3,
then what is the most efficient way to check the existence of the file?

Any suggestions will be highly appreciated.

Regards,
Jevgeni Astanovski.