topic Does REDUCE perform better using sorted tables? in Application Development and Automation Discussions

Does REDUCE perform better using sorted tables?

matteo_pascon — Fri, 16 Jun 2023 09:35:27 GMT

So, I'm using reduce to get the number of record that satisfy a condition inside a loop.

Will it perform better if the table is declared as sorted using a logic similar to that of parallel cursor or does it actually just check linearly?

The code is as follow.

DATA(sum) = REDUCE i( INIT x = 0 FOR wa IN lt_iloa WHERE ( tplnr = ls_ifl_list-tplnr ) NEXT x = x + 1 ).

Re: Does REDUCE perform better using sorted tables?

fedaros — Fri, 16 Jun 2023 12:33:31 GMT

Hi Matteo,

Yes, it will take the advantage of access by key on tplnr and will not run entire internal table. So the difference of execution can be huge and with a constant result time benefit from indexed access.

Regards, Fernando Da Rós

Re: Does REDUCE perform better using sorted tables?

matteo_pascon — Fri, 16 Jun 2023 13:19:08 GMT

Wonderful! Thanks for the insights.

Re: Does REDUCE perform better using sorted tables?

Sandra_Rossi — Fri, 16 Jun 2023 13:51:00 GMT

matteo_pascon as documented in ABAP documentation FOR, cond > "As with LOOP AT itab, the following is possible for each expression FOR ... IN itab" > LOOP AT itab, cond :

"If the primary table key is specified using its name primary_key, the processing behaves in the same way as if no key were explicitly specified."
etc.

Re: Does REDUCE perform better using sorted tables?

matteo_pascon — Fri, 16 Jun 2023 15:38:29 GMT

Got it. Thanks for sharing the documentation.