Re: DataArea vs. Tables

Larry....

That's an interesting post, and it contradicts what I've heard in the
past. Namely that writing to a *DTAARA is faster than writing to a
table due to the lack of RDMS overhead.

Was the *DTAARA in question journaled by chance? I could understand
if the journal entries for the DTAARA were forced to disk as the same
thing happens for a journaled file that's updated without using
commitment control. I don't believe you can use commitment control on
a DTAARA...

The idea that a DTAARA is always automatically forced to disk seems to
go against the grain of single level store.

Is this documented by IBM somewhere?

Charles

On Fri, May 13, 2011 at 4:48 PM, DrFranken <midrange@xxxxxxxxxxxx> wrote:

Use them infrequently but have discovered one technical difference
between the use of a *DTAARA and a table.

If you write to a *DTAARA the system forces the write to disk. Now if
you have write cache on your disk controllers the write to that cache is
considered 'well enough' and processing continues. However if you have
no cache (as a low end system with mirrored disk might have) then the
write must be actually to disk. When using for a 'next order' number and
such things this is no problem, however if you are updating the *DTAARA
with (say) current record position in a massive table (for crash
recovery for example) then EVERY record position gets forced to disk and
that slows the job *DRAMTICALLY. If you are using a table or traditional
database file then the O/S caches that data preventing every write from
hitting physical disk.

Potentially a rare case I grant you but finding it out at 2AM (when I
did) was not pleasant.

- Larry "DrFranken" Bolhuis

On 5/13/2011 11:17 AM, Birgitta Hauser wrote:

Hi guys,



we just had a discussion about using data areas.

In my opinion they are not heavily used or needed.

I either create a table/physical file or store the information in global
variables in a specific service program. The data within these global
variables is set and retrieved by calling procedures.



I’m just curious, are you using data areas (heavily) or not?



Mit freundlichen Grüßen / Best regards



Birgitta Hauser



"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)

"If you think education is expensive, try ignorance." (Derek Bok)

"What is worse than training your staff and losing them? Not training them
and keeping them!"

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