RE: Records written to a file don't show up immediately

[CWilt@xxxxxxxxxxxx]

My understanding:

Prior to v5r2, FEOD actually force the records to be written out to disk.

At v5r2, the 'N' operation extender was added that causes the records to be
written out to the DB from the buffer but does not necessarily cause the
records to be written to disk.

So FEOD was pretty "expensive", but with the new extender it's not so much.

However, FRCRATIO itself is concerned about writing to disk instead of just
the DB.  So it should be just as expensive as FEOD w/o the extender.

To the original poster, as other have said, the problem is that RPG buffers
the writes to the DB.  This is fine with a batch program, but for an
interactive program you should really turn the buffer off.  The way to do
this is simply to use:
OVRDBF SEQONLY(*NO)


There was a rather detailed discussions about RPG and buffering not to long
ago:
http://archive.midrange.com/rpg400-l/200408/msg00302.html

In particular check out this link to an IBM Technote of the subject:
http://www-1.ibm.com/support/docview.wss?uid=nas1d6738e1cd37e1f33862565c2007
cef79&rs=110
 or
http://tinyurl.com/47y5r

>From the technote:
Interactive - To match the size of an interactive screen (presumes the
application presents eight records on a screen) one set of data presented to
a user interactively (SEQONLY *YES 8). Most interactive applications' writes
are probably best coded as immediate writes (SEQONLY *NO). An alternative
commonly mentioned is to use the FEOD operation to force the buffer (and
while this does force the writes to the database, it also causes the data to
be forced to secondary storage (DASD) and makes it likely that the page on
which the data resides will be stolen). FEOD is almost always less efficient
from a system-wide perspective than using single writes. 

(note: I think they are talking FEOD w/o the extender here)


Come to think of it Dan, you had some posts in that discussion....

HTH,
Charles


> -----Original Message-----
> From: Dan Bale [mailto:dbale@xxxxxxxxxxxxx]
> Sent: Monday, September 27, 2004 10:24 AM
> To: RPG programming on the AS400 / iSeries
> Subject: RE: Records written to a file don't show up immediately
> 
> 
> It was my impression that FEOD is relatively expensive, 
> especially if you're
> doing it after every record being output.  Well, perhaps for 
> an interactive
> program it may be acceptable.
> 
> > FRCRATIO will work but is also
> > easier to change by more people....
> 
> Hmmmph.  Don't know why that is.  Well, then, stick the 
> override in the RPG
> program.
> 
> > -----Original Message-----
> > From: rpg400-l-bounces@xxxxxxxxxxxx / Holden Tommy
> > Sent: Monday, September 27, 2004 9:47 AM
> >
> > FEOD is what I prefer in this case.  the FRCRATIO will work 
> but is also
> > easier to change by more people....
> >
> > Thanks,
> > Tommy Holden
> 
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