Performance Tuning using Parallel Cursor

Nested Loops – This is one of the fear factors for all the ABAP developers as this consumes lot of program execution time. If the number of entries in the internal tables is huge, then the situation would be too worse. The solution for this is to use parallel cursor method whenever there is a need for Nested Loop.

Program using Normal Nested Loop:

REPORT ZNORMAL_NESTEDLOOP.

TABLES:
likp,
lips.

Data:
t_likp type table of likp,
t_lips type TABLE OF lips.

data:
W_RUNTIME1 TYPE I,
W_RUNTIME2 TYPE I.

START-OF-SELECTION.
select *
from likp
into table t_likp.

select *
from lips
into table t_lips.

get RUN TIME FIELD w_runtime1.

loop at t_likp into likp.
loop at t_lips into lips where vbeln eq likp-vbeln.
endloop.
endloop.

get RUN TIME FIELD w_runtime2.

w_runtime2 = w_runtime2 - w_runtime1.

write w_runtime2.

Nested Loop using Parallel Cursor:

REPORT zparallel_cursor2.

TABLES:
likp,
lips.

DATA:
t_likp TYPE TABLE OF likp,
t_lips TYPE TABLE OF lips.

DATA:
w_runtime1 TYPE i,
w_runtime2 TYPE i,
w_index LIKE sy-index.

START-OF-SELECTION.
SELECT *
FROM likp
INTO TABLE t_likp.

SELECT *
FROM lips
INTO TABLE t_lips.

GET RUN TIME FIELD w_runtime1.
SORT t_likp BY vbeln.
SORT t_lips BY vbeln.

LOOP AT t_likp INTO likp.

LOOP AT t_lips INTO lips FROM w_index.
IF likp-vbeln NE lips-vbeln.
w_index = sy-tabix.
EXIT.
ENDIF.
ENDLOOP.
ENDLOOP.

GET RUN TIME FIELD w_runtime2.

w_runtime2 = w_runtime2 - w_runtime1.

WRITE w_runtime2.

Analysis report: Runtime in microseconds:

Iteration No	Normal Nested Loop	Using Parallel Cursor
1	34,796,147	63,829
2	38,534,583	56,894
3	34,103,426	50,510