Re: Need ideas to reduce open/close in RPG program

This is more theory than anything because I'm not at a computer to try it.
Being flexible is great but how flexible is what you might ask yourself and at what cost. I would engineer it so that it reads the list of files only once at program startup. If you want to add or remove to the list of files then you have to end the job and resubmit it again.
Open all the files once and keep them open.
You then just have to perform the updates as you receive the change data. .

Glenn Gundermann
glenn.gundermann@xxxxxxxxx
416-317-3144

-----Original Message-----
From: Vinay Gavankar <vinaygav@xxxxxxxxx>
Sender: "RPG400-L" <rpg400-l-bounces@xxxxxxxxxxxx>Date: Fri, 11 Dec 2015 18:42:31
To: RPG programming on the IBM i (AS/400 and iSeries)<rpg400-l@xxxxxxxxxxxx>
Reply-To: "RPG programming on the IBM i \(AS/400 and iSeries\)"
<rpg400-l@xxxxxxxxxxxx>
Subject: Need ideas to reduce open/close in RPG program

Hi,

We have a program which receives some values thru Data Queue read and it
updates a file with the values received.

The problem is that there are multiple copies of the file it needs to
update.

Let us say it is updating FILEA, so that is what is in the compiled code.

On the system there are currently 15 files which are exact copies of this
file. They have a different file name, but the the same record format name,
field names etc.

The program reads a 'control' file, which has the names of these 15 files.
For every file, it does an OVRDBF of FILEA to the actual file name, Opens
the file, updates/writes the record, and then Closes the File.

The system was built for 'flexibility' years back, when they started with 2
or 3 files. It is flexible, in the sense it did not need a code change as
the files being updated grew from 3 to 15.

This is a very 'busy' program, meaning it is constantly receiving data thru
the data queue. Actually there are multiple copies of this program running
simultaneously receiving data from the same data queue and all of them are
pretty busy.

Now they are finding that all these open/closes are seriously impacting the
CPU usage.

An architectural change is obviously indicated, but that would take time to
implement.

As usual, they are looking for a 'short term', quick and dirty fix (to be
implemented in 2 weeks) to eliminate these open/close.

The only thing we could think of was to define the current 15 files
separately in the program and then update them as needed, losing all
flexibility.

Any other ideas or suggestions would be greatly appreciated.

TIA