Re: SQL performance

Hi Marco,

Am 21.08.2024 um 10:43 schrieb Marco Facchinetti <marco.facchinetti@xxxxxxxxx>:

Hi Daniel, thanks for you time.

You're very welcome.

I agree about data sets and, when possible, I design SQL acces in that way
but in this specific program obtaining the customer's list (ABCDUTENTE) is
too complex with SQL.

I also often think that - sometimes you have to find a "middle way".

The program with the cursor works and is completely satisfactory but I
would like to know why with the Select the times are so high. Is it a
problem in the links between the tables? In the conditions or in the
sequence in which they are specified?

Yes - all those things shouldn't - but can have an influence on the statement execution.

Do I understand the code correctly - you only fetch ONE row and then close the cursor again?

Or do you leave the cursor open, and fetch one row after another in a loop?

What puzzles me is why a cursor is so fast (2/3 SECONDS) and a Select takes
20 MINUTES. The code of the Select and of the Cursor is exactly the same
and the general logic too: will be executed 1.260 times.

Yes - those differences are really big - that looks suspicious.

Regards,
Daniel