Re: RPG Blocked Writes

Yes, but with SQL that is a mute issue. You are always going to define a
primary key and that is always a unique key on the physical. Also, I don't
think it would make any difference if you had a logical with unique keys.
Unless you remove the logicals, write and then add back you should get the
same effect.

On Mon, Jun 7, 2010 at 4:38 PM, Kurt Anderson
<kurt.anderson@xxxxxxxxxxxxxx>wrote:

Aha, so it sounds like there is a reason to not key a physical? I thought
that the "sequential" and "keyed" access to a file as mentioned by the
document was in regard to what opcodes I was using, not the actual access
path. Bummer. However, good to know. A while back I had asked if there
was any reason to not key a PF, and I don't recall that being an issue,
however I may have also missed it.

Thanks,
Kurt

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Alan Campin
Sent: Monday, June 07, 2010 5:30 PM
To: RPG programming on the IBM i / System i
Subject: Re: RPG Blocked Writes

Are there unique keys on the table? That will change it to single record
I/O.

On Mon, Jun 7, 2010 at 4:22 PM, Kurt Anderson
<kurt.anderson@xxxxxxxxxxxxxx>wrote:

I have a file defined in a program as:

FFileA O A E K Disk

From my understanding, writes to this file should be blocked. However

when I look at the I/O for the job, the I/O count and the RRN is always
equal. For comparison, reading a file that's blocked has a lower I/O

count

than the current RRN.

Is this a matter of me not understanding the I/O screen (when looking at
the job as it is running), or is this file actually writing a single

record

at a time?

According to this document, I feel that these writes should be blocked.

https://www-912.ibm.com/s_dir/slkbase.NSF/1ac66549a21402188625680b0002037e/d6738e1cd37e1f33862565c2007cef79?OpenDocument

"All high-level language programs (HLLs) use blocking at certain times

and

use single record I/O at other times, based on program specifications.
Because blocking takes less system resources to perform a single I/O, a
program that blocks performs better and uses less system resources. The
default for the HLL uses record blocking if opening a file for output

only

(write) or input only (read)."

Thanks,
Kurt Anderson
Sr. Programmer/Analyst
CustomCall Data Systems
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