Dynamic SQL for multiple data libraries (was Re: SQL with parameters - need to PREPARE and 'OPEN ... USING'?)

(moved from RPG list)

So did switching to dynamic SQL help performance?

Seems a bit strange to me...

At worst, I'd expect a re-plan for a static statement to perform no worse
than building a plan for a dynamic statement.

At best, I'd think a re-plan for a static statement to be better than
building one for a dynamic statement.

Perhaps Chuck or one of the others on here with more knowledge of the
internals will chime in.

Charles


On Wed, May 11, 2016 at 1:56 PM, <dlclark@xxxxxxxxxxxxxxxx> wrote:

"RPG400-L" <rpg400-l-bounces@xxxxxxxxxxxx> wrote on 05/11/2016 01:39:55
PM:

I assume you had a PMR open? The answer they came back with was to use
dynamic SQL?

There was no PMR. We were having performance issues and we hired
IBM to, among other things, take a look at our SQL usage and to advise us
the correct/best way to use SQL. One of the things that came out in the
process was that our environment has nearly 600 "local" data libraries
with the same tables in every library plus we have a "shared" data
library. Library lists will have one "local" data library and the one
"shared" data library in them. "Local" users don't switch library lists
for their interactive sessions but some of the jobs that run on their
behalf have to switch library lists to process all of the files. The
resulting IBM recommendation to us was to use static SQL for the "shared"
data library but to use dynamic SQL for the "local" data libraries. We
also contracted for SQL training and the trainer agreed regarding our
situation with the same table names in multiple data libraries.

Sincerely,

Dave Clark
int.ext: 91078
direct: (937) 531-6378
home: (937) 751-3300

Winsupply Group Services
3110 Kettering Boulevard
Dayton, Ohio 45439 USA
(937) 294-5331





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