Avoid String Concatenation Inside Loops

WarningPerformance & Database#EC NO_CONCAT_LOOPRemote Enabled

Overview

Avoid string concatenation inside loops.

ATC Finding Message: Accumulate parts in a table and concatenate once

Rationale

Repeatedly appending to the same string inside a loop copies the accumulated result on every iteration, which turns a linear operation into a quadratic one for large tables. Collect the parts in a string table and join them once, or use a suitable aggregation. Keep the concatenation outside the loop whenever possible.

Non-Compliant

LOOP AT lt_names INTO lv_name.
  lv_result = lv_result && lv_name.
ENDLOOP.

Compliant

LOOP AT lt_names INTO lv_name.
  APPEND lv_name TO lt_parts.
ENDLOOP.
lv_result = concat_lines_of( table = lt_parts ).

Suppression

To suppress findings for this rule, append the pseudo-comment to the statement:

" Standard pseudo-comment:
... "#EC NO_CONCAT_LOOP

" SAP CI_ prefix format:
... "#EC CI_NO_CONCAT_LOOP

Technical Details

• Native ATC Class: ZCL_SKYLINT_NO_CONCAT_LOOP
• Implementation File: zcl_skylint_no_concat_loop.clas.abap