Re: Repeated CLOSE and OPEN of SQL cursors

Not an answer to your question as such - but this is why I never re-issue an SQL statement just to get a different ORDER BY.

My approach is that the initial SQL loads a DS array and the subfile is populated from that.

If required the DS is then sorted (qsort of SORTA) and redisplayed.

Reason is my belief (and personal experience) that when a user says "sort the data this way" they mean the data they are _looking_ at. If there is any chance that the table has changed in the interim period they can get very confused.


Jon P

On Oct 10, 2022, at 9:26 AM, Alan Cassidy <cfuture@xxxxxxxxxxx> wrote:

I have one last thing stumping me for now to finish a major code change to boost performance in one program I'm working on, relating to SQL cursors.

The RPG program opens an SQL cursor and the entire subfile is input. Then the user requests a different "ORDER BY" than the default. I use the same SQL for the sort, the whole thing is identical except for tacking on the different ORDER BY clause at the end of the dynamically constructed SQL statement.

At the top of the subroutine that does the cursor open, the code first does an Exec SQL Close M1, where M1 is the cursor. Then re-open. So if this is the second or third time, etc., opening the cursor, the code first runs the line "exec SQL Close M1".

The issue is that the sorted open is getting sometimes around two or three times (it varies) as many rows returned as the first open.

Can someone point me to why or how that could happen?

--Alan Cassidy



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