RE: lose data during system crash -- RPG400-L

Nice recap... I'll just mention that IBM offers a PRPQ which enables cache journal buffering, which relieves some of the overhead of journaling sans commitment control, but then leaves the system vulnerable to lost journal transactions in the event of a hard crash.... :(

Eric

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Wilt, Charles
Sent: Tuesday, October 30, 2007 7:21 AM
To: RPG programming on the AS400 / iSeries
Subject: RE: lose data during system crash

True. Journaling does provide that benefit.

However, when journaling is used by itself the journal effectively has a FRCRATIO(1).

So the same performance issues regarding having FRCRATIO(1) of the file itself apply. Maybe not quite
as bad if your journal receivers are on a separate ASP.

On the other hand, if you use journaling + commitment control, then the system is able to cache the
journal entries until they are committed. This is why you can often see performance increase when
adding commitment control to a process whose files are already journaled.

HTH,
Charles

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Raul A. Jager W.
Sent: Tuesday, October 30, 2007 7:57 AM
To: RPG programming on the AS400 / iSeries
Subject: Re: lose data during system crash

Will journaling help? I understand that journaling will
recover the lost data during IPL.

Mark S. Waterbury wrote:

Hi, Charles:

Of course, it depends on the frequency of updating these

"next numbers"

and also, whether this is done in interactive jobs, or in

batch, etc.,

and this must be weighed against the additional cost of

recovery when

they have to deal with and "clean up" these "duplicate"

records, as is

the case now, after a failure has occurred. (Like most things to do
with "performance", there are always "trade-offs".)

Note that I did not suggest changing FRCRATIO for ALL files,

but only

for this "next number" master file.

This is exactly why IBM added support for FRCRATIO.

Regards,

Mark S. Waterbury

Wilt, Charles wrote:

Note that changing FRCRATIO will impact performance negatively.

It's not usually the "right" answer.

Charles

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Lim Hock-Chai
Sent: Monday, October 29, 2007 5:24 PM
To: RPG programming on the AS400 / iSeries
Subject: RE: lose data during system crash

Thanks Scott, that explain the cause of problem. I didn't

know that

there are two layers of memory involved.

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Monday, October 29, 2007 4:20 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: lose data during system crash

Blocking controls how often RPG sends the records from

it's memory to

the database's memory.

FRCRATIO controls how often the database software writes

it's memory

to disk.

Lim Hock-Chai wrote:

Hhmmm. Reading the help text on the command, I guess that is the
problem. The file has FRCRATIO(*NONE). Here is the part

that I'm

confused about. In RPG, data blocking(buffering) should

only happen

if file is opened with output only. This RPG program is

opening this

file with UPDATE only. Did I missing something?

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