Re: Accessing Database vs Dataarea

"RPG400-L" <rpg400-l-bounces@xxxxxxxxxxxx> wrote on 04/22/2017 01:00:02
PM:

----- Message from Vinay Gavankar <vinaygav@xxxxxxxxx> on Fri, 21
Apr 2017 17:42:56 -0400 -----

To:

"RPG programming on the IBM i (AS/400 and iSeries)"

<rpg400-l@xxxxxxxxxxxx>

Subject:

Accessing Database vs Dataarea

Hi,

We have a program where same record of a 'control' file (input mode) is
being read for every iteration, and I thought that replacing the 'Chain'
with reading a dataarea.

So I ran a simple test to compare the time taken to read one record in

file

100,000 times and reading a data area 100,000 times with 'IN' statement.

I was surprised that the file was read under 1 sec, whereas dataarea

took

around 4-5 seconds.

Just to make sure, I looped for a million times. The file came in at 4
seconds and dataarea at 47 seconds.

I was wondering whether I am missing something or accessing a dataarea

with

an 'IN' statement takes that long compared to file read.

Just to be clear, does the IN operation specify *LOCK? If so, that would
explain part of it.

I would love to hear from someone with some knowledge about the internal
implementation of IN. i.e., Is the data area object and associated
pointers resolved each time?

Odd results indeed.

Michael Quigley
Computer Services
The Way International
www.TheWay.org