Using Sorted table and Index while processing Internal tables

There would have been many instances where we would have to process large entries in an internal table with a WHERE condition. This article is intended to demonstrate the comparison between three different methods in handling this situation.

First Method: The normal method used by most of us. Standard internal table processing using WHERE condition

Second Method: Same as above, but here we would be using the Sorted table

Third Method: Sorted table and using the Index

Following is the demo program illustrating the above three methods:

REPORT ZINTERNAL_TABLE_OPERATIONS.

* Program to find the best method in reading the internal tables
* Author: Suresh Kumar Parvathaneni

* Type declaration
TYPES:
 BEGIN OF TY_MARA,
   MATNR LIKE MARA-MATNR,
   MTART LIKE MARA-MTART,
 END OF TY_MARA.

* Internal table declaration
DATA:
 T_MARA TYPE STANDARD TABLE OF TY_MARA,
 T_MARA1 TYPE SORTED TABLE OF TY_MARA
         WITH NON-UNIQUE KEY MTART.

* Variable declaration
DATA:
 W_COUNTER TYPE I,
 W_RUNTIME1 TYPE I,
 W_RUNTIME2 TYPE I,
 W_TABIX LIKE SY-TABIX.

* Table workarea definition
DATA:
 WA_MARA TYPE TY_MARA.

SELECT MATNR                           " Material Number
      MTART                           " Material Type
 FROM MARA
 INTO TABLE T_MARA.

T_MARA1[] = T_MARA[].

* CASE 1: Processing internal table using LOOP..WHERE Condition

GET RUN TIME FIELD W_RUNTIME1.

LOOP AT T_MARA INTO WA_MARA WHERE MTART EQ 'FHMI'.
 ADD 1 TO W_COUNTER.
ENDLOOP.

GET RUN TIME FIELD W_RUNTIME2.
* Calculate Runtime
W_RUNTIME2 = W_RUNTIME2 - W_RUNTIME1.
WRITE W_RUNTIME2.

CLEAR W_COUNTER.

* CASE 2: Using a Sorted table

GET RUN TIME FIELD W_RUNTIME1.
LOOP AT T_MARA1 INTO WA_MARA WHERE MTART EQ 'FHMI'.
 ADD 1 TO W_COUNTER.
ENDLOOP.

GET RUN TIME FIELD W_RUNTIME2.
* Calculate Runtime
W_RUNTIME2 = W_RUNTIME2 - W_RUNTIME1.
WRITE W_RUNTIME2.

CLEAR W_COUNTER.

* CASE 3: Using INDEX on a sorted table

GET RUN TIME FIELD W_RUNTIME1.
READ TABLE T_MARA1 INTO WA_MARA WITH KEY MTART = 'FHMI'.
IF SY-SUBRC EQ 0.
 W_TABIX = SY-TABIX + 1.
 ADD 1 TO W_COUNTER.
 LOOP AT T_MARA1 INTO WA_MARA FROM W_TABIX.
   IF WA_MARA-MTART NE 'FHMI'.
     EXIT.
   ENDIF.
   ADD 1 TO W_COUNTER.
 ENDLOOP.
ENDIF.
GET RUN TIME FIELD W_RUNTIME2.
* Calculate Runtime
W_RUNTIME2 = W_RUNTIME2 - W_RUNTIME1.
WRITE W_RUNTIME2.

Following is the analysis report in microseconds, as per the data volume:

Records: 21,390

Iteration No	Using Normal LOOP & WHERE	Using Sorted table LOOP & WHERE	Using INDEX on Sorted table
1	897	887	11
2	839	879	10
3	839	877	10
4	834	880	9
5	842	837	10

Records: 132,693

Iteration No	Using Normal LOOP & WHERE	Using Sorted table LOOP & WHERE	Using INDEX on Sorted table
1	34239	35774	3567
2	34271	38250	3592
3	34492	36534	3554
4	34198	35695	3584

Sorted table might have given a better performance here if the field in the WHERE condition is the first field in the internal table. However, from the above statistics, we can say that method 3 is better than the other 2 methods. In production environment, the data would be huge and the performance could be much improved with this simple technique.