RE: RPG Blocked Writes

I suppose it's possible that MAINT(*IMMED) is causing this. But in general,
unique key requirement causes MAINT(*IMMED) to be required, and one or the
other of those attributes causes non-buffered writes.

You're sure there are no unique indexes that you've overlooked or forgotten?
But in any case (my point) moving your keys to LF won't help this situation.
The DB has the same work to do in either case.

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"This is the most extraordinary collection of talent, of human knowledge,
that has ever been gathered together at the White House -- with the possible
exception of when Thomas Jefferson dined here alone."
-- John F. Kennedy (to Nobel Prize winners)

In this particular case, the physical is keyed, as are some logicals,
although none of them are Unique keys.

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-
bounces@xxxxxxxxxxxx] On Behalf Of Dennis Lovelady
Sent: Monday, June 07, 2010 5:50 PM
To: 'RPG programming on the IBM i / System i'
Subject: RE: RPG Blocked Writes

Not keying the physical won't help, if you have unique keys elsewhere.
The
result is a constraint on the file that must be checked with each write
-
and that means a physical write with each logical write.

I personally feel it's best to put your unique keys on the physical,
but
again that won't impact the performance you're measuring.

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"Abstract Art: A product of the untalented, sold by the unprincipled to
the
utterly bewildered."
-- Al Capp

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/d6738e1c

d37e1f33862565c2007cef79?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