Re: Service Program Overhead

Oops, yes what was supposed to be CPYTOIMPF, sorry about that.

It seemed to work pretty fast for me. I prefer to write a CSV as you suggest
though directly from RPG. I hate using work tables if I don't have to.

--
James R. Perkins
http://twitter.com/the_jamezp


On Fri, Nov 13, 2009 at 11:12, Kurt Anderson
<kurt.anderson@xxxxxxxxxxxxxx>wrote:

Hi James,

I don't know if things have changed, but historically I've always seen
significantly slower times when using CPYTOSTMF than when writing to the IFS
directly from RPG via APIs (and writing directly from RPG to the IFS also
has the benefit of skipping intermediary processing such as writing to a
temp file before passing it along).

I know you said you used CPYFRMINPF to export the file to CSV, but I guess
that confuses me b/c from the looks of it that command copies the file from
the IFS to your library.

Some info on writing directly to the IFS via RPG:
http://www.news400.com/resources/clubtech/tnt400/bo400ng/AS400Q0167.htm

-Kurt Anderson

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of James Perkins
Sent: Friday, November 13, 2009 12:45 PM
To: RPG programming on the IBM i / System i
Subject: Service Program Overhead

Hello All,
I had to write a program to write DB data to a stream file in comma
delimited format. No problem, done it many of times. Then I ran into a
problem, running the program seemed to take hours. Well, I determined that
was a bad subprocedure on my part, so I fixed that and it now takes only
about 5 minutes to run.

While doing this doing this I tried a couple of other approaches. I wrote
the data to a table and used CPYFRMIMPF to export it to a CSV, this took
about 1 minute 40. I also wrote a simple Java program to execute an SQL
statement and write the results to a stream file, this took about 1 minute
10. ** Note, there was no scientific approach to the time calculation, just
simple start and end times.

It seems that the invocation of subprocedures in a service program
significantly slows down performance. I invoke 2 subprocedures on each
write
to the stream file, a replace all subprocedure and the write line
subprocedure. So, for the question, what kind of overhead is there when
invoking subprocedures from a service program? I'm sure there is
information
on this, I just can't seem to find it.

Thanks in advance,
--
James R. Perkins
http://twitter.com/the_jamezp
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