topic Re: Performance Improvement on LOOP AT in Application Development and Automation Discussions

Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 13:59:10 GMT

Hi all

Here is the snapshot from a program :

****************************************************************

constants: charnull(1) TYPE x VALUE '00'.

DATA: BEGIN OF adr3_tab OCCURS 0,

.....

chngind(1) TYPE x,

END OF adr3_tab.

SELECT addrnumber persnumber date_from consnumber country flgdefault

fax_number fax_extens faxnr_long fax_group

INTO TABLE adr3_tab

FROM adr3.

LOOP AT adr3_tab.

adr3_tab-chngind = charnull.

MODIFY adr3_tab.

ENDLOOP.

**************************************************

Above Loop eats more CPU time !

How could we improve the performance ?

Any advice ?

Thanks

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 14:04:51 GMT

Try to use work area in ur internal table.

Performance Improvement on LOOP AT

Posted: Jun 21, 2007 7:29 PM

constants: charnull(1) TYPE x VALUE '00'.

DATA: BEGIN OF adr3_tab OCCURS 0,

.....

chngind(1) TYPE x,

END OF adr3_tab.

Data: it_adr3 type standard table of adr3_tab,

wa_adr3 type adr3_tab.

SELECT addrnumber persnumber date_from consnumber country flgdefault

fax_number fax_extens faxnr_long fax_group

INTO TABLE it_adr3

FROM adr3.

LOOP AT it_adr3 into wa_adr3.

wa_adr3-chngind = charnull.

MODIFY it_adr3 from wa_adr3.

ENDLOOP.

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 14:05:22 GMT

Hello,

Try like this.


adr3_tab-chngind = charnull.
modify adr3_tab TRANSPORTING chngind where chngind is initial.

REgards,

Vasanth

Re: Performance Improvement on LOOP AT

Peter_Inotai — Thu, 21 Jun 2007 14:26:34 GMT

Try field symbol...something like this:

field-symbols: <lwa_adr3_tab> type ...

loop at adr3_tab assigning <lwa_adr3_tab>.
 <lwa_adr3_tab>-chngind = charnull.
* No need for modify!!!!
endloop.

This way nothing is copied from the internal table to the header line, so it will be faster.

Peter

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 14:46:35 GMT

Peter Inotai

Since I have millions(nearly 20 m) of Records on the Internal Table, will the LOOP AT again cause problem ?

Thanks

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 14:50:03 GMT

Hello Remo J,

Field symbols its the faster way to loop on an internal table.

You will have no problem for Peter´s proposal

Hope this helps

Gabriel

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 14:51:23 GMT

LOOP AT ITAB ASSIGNING <FS> cuts out the "copy cost" which occurs with LOOP AT ITAB INTO <WA> or LOOP AT ITAB (data is copied into the headre line here. For efficiency, field symbols should be used whenever possible.

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 14:56:29 GMT

Hi all

Why the following Stmt is not efficient when comparing Field-symbols:

<b> adr3_tab-chngind = charnull.

modify adr3_tab TRANSPORTING chngind where chngind is initial.</b>

Also it does not uses even LOOP AT !

I feel this stmt works for all record on a single time ! Please correct me if I am wrong.

Regards

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 15:04:02 GMT

Hi Remo,

Yes, You are corect.

modify adr3_tab TRANSPORTING chngind where chngind is initial. This statement does not need LOOP..ENDLOOP and will modify the reocrds which satisfies the condition.

Thanks,

Vinay

Re: Performance Improvement on LOOP AT

Former Member — Thu, 21 Jun 2007 15:14:36 GMT

Hi all

Using the Field-symbols inside the LOOP, do I have clear its current content using clear stmt inside the LOOP!

loop at adr3_tab assigning <lwa_adr3_tab>.

<lwa_adr3_tab>-chngind = charnull.

No need for modify!!!!

<b>clear <lwa_adr3_tab>.</b>

endloop.

Is it required clear the content before the next loop contents gets pointed using FS ?

Regards

Re: Performance Improvement on LOOP AT

Former Member — Fri, 22 Jun 2007 09:37:29 GMT

Any one !

Re: Performance Improvement on LOOP AT

Former Member — Fri, 22 Jun 2007 09:42:37 GMT

hello Remo,

Field-symbols are the fastest way to operations on intarenal table,.

u should never use the clera statement for feilds symbols abecause it direclty work on the internal table body. unles and until if u want to clear the purticular record in the itab

Re: Performance Improvement on LOOP AT

jayanthi_jayaraman — Fri, 22 Jun 2007 09:43:02 GMT

Hi,

This is from documentation.So as far I know,since it is only pointing no need toclear.

In "LOOP AT itab ASSIGNING <fs>", the field symbol <fs> points to the selected entry, that is, the line is not copied into a work area. You cannot reassing the field symbol to another line of the table or another field within the loop.