Re: GET DIAGNOSTICS question

Charles, there are ordering and select/onit business rules that make using
a data queue impractical. Manual intervention removes some orders, some
orders must be processed immediately, and there is real-time management
reporting (analysis of the backlog). Database technology handles the
selection and ordering perfectly and such logic can be emulated on
other platforms. I use data queues where strict FIFO rules apply; that's
not the case here.

The EOFDLY keyword forces a wait on an input primary file; I use
this feature in other areas.

There will be a time when a programmer looking at this code will have to
dig out a manual to learn what SETLL does. I'm just proactively reducing
technical debt!

-rf

On Thu, May 11, 2023 at 11:58 AM Charles Wilt <charles.wilt@xxxxxxxxx>
wrote:

Honestly,

My 0.02 ... you're using the wrong object...

Instead of reading a file, with SQL, you should be reading a queue.

Otherwise go back to the RLA access ... IIRC there's a way to have the RPG
wait for a record to appear in the file.

Charles

On Wed, May 10, 2023 at 7:22 PM Reeve <rfritchman@xxxxxxxxx> wrote:

Charles, thanks. WRT to your suggestion of sleeping regardless, I'm
pricing orders entered moments before and there is a sense of urgency/not
getting backlogged with the pricing process. If I get to the end of the
data, I want a quick check to see if any new data has shown up. That's

the

point where I want to tickle SQL and find out if new orders have arrived.

The previous code used a keyed logical file with select/omit's and *IMMED
access path maintenance. I suspect that is the equivalent of a SENSITIVE
cursor and I'm going to give it a try.

Buck's suggestion of doing a SELECT COUNT(*) will work but I do have
several selection conditions.

Cheers,
rf

On Wed, May 10, 2023 at 3:04 PM Charles Wilt <charles.wilt@xxxxxxxxx>
wrote:

DB2_NUMBER_ROWS works, but you have to open an INSENSITIVE
cursor...otherwise it's just a guess..
ie. The Db will make a copy of the data...

DB2_NUMBER_ROWS
If the previous SQL statement was an OPEN or a FETCH which caused the

size

of the result table to be
known, returns the number of rows in the result table. For SENSITIVE
cursors, this value can be
thought of as an approximation since rows inserted and deleted will

affect

the next retrieval of this
value. Otherwise, the value zero is returned.


Personally, if you want to process to the end anyway, I'd just do so

and

take a nap when you run out of data.

Charles

On Wed, May 10, 2023 at 2:38 AM Reeve <rfritchman@xxxxxxxxx> wrote:

How do I determine the number of records in the cursor I've just

opened?

GET DIAGNOSTICS :x = ROW_COUNT returns the number of rows

processed--not

what I need here. GET DIAGNOSTICS :x = DB2_NUMBER_ROWS seems to be

the

right call but it gives me a nonsense (I think) number (14932) when

there

are zero rows. If I have zero rows available, I close the cursor,

sleep,

wake up, open the cursor again, and check for available rows.

The goal is to put this application (a daemon) to sleep when there

are

no

records to process. Yes, I could go old skool and do an EOF-DELAY

(but

application logic precludes arrival sequence) , data queue is the

same

reason, or a file status data structure (the pre-SQL way). A
workaround isn't hard--I'd just count the number of records processed

when

SQLSTT = '02000'; if the number is zero, then there are no rows

available

and I'll take a nap. As I think about it, ROW_COUNT would be the
perfect solution--it's intuitive.

Sidebar question: what's the format for using VALUES and GET

DIAGNOSTICS

in

Run SQL Scripts?

Thanks!

-rf
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