RE: Slow respond time when file change to open with update&Add -- RPG400-L

thanks for the respond and yes, due to some changes to Business requirements, 
chain and update is required.

The think I don't quite understand is that , the program actually doing quite a 
bit of checking (filtering) logics before write/update the outfile.  I don't 
see why it would double the processing time by simply adding a chain.  That is 
why I think the record blocking is the cause of the problem.
Out of 1.2 mil+ added to the file, there will probably only 100+ records that 
the chain will actually get a %found.  ==> Loading record to the buffer should 
not be the cause of the problem.
 

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Mark A. Manske
Sent: Wednesday, April 28, 2004 4:40 PM
To: 'RPG programming on the AS400 / iSeries'
Subject: RE: Slow respond time when file change to open with update&Add


Lim,

You mention the "only" logic change is for a chain to the outfile, then
update or write
as appropriate.  The time increase is right there, your disk I/O has just
doubled, so has your time.
Record blocking cannot do much for you, since you now will update or write a
record based upon
only one record at a time.  If you business requirements are forcing the
need to do the chain, and
do an update or add, then you are stuck with a longer running program -
those disk heads are very busy.
If you are flexible in your business requirements, change back to just
writing records.

HTH
Mark


-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Lim Hock-Chai
Sent: Wednesday, April 28, 2004 4:09 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: Slow respond time when file change to open with update&Add


I created a RPG program that reads an input file that contains about 2.5
mil+ records and write them to a output file if they meeting the criteria
(about 1.2 mil+ records).
 
1) It took about 35 mins to run when the input file is open as Input only
with sequential access (No Key).  The output file is open as output only.
2) It took about 70 mins to run when the program is change to open the input
file as Input only with key access and the outfile as Update & Add.  The
only logic added to the program is it do a chain to outfile, if %found,
update, otherwise write.
 
I think the increase of processing time on 2 is cause the outfile open as
Update&ADD, which cause the program to not do record blocking when write to
outfile.
 
I got several methods in mind that I can think of that might speed up 2.
However, just wonder if anybody has had the same problem before and know a
good method to speed it up.
 
thanks
 
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