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basic performance techniques

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Former Member

‎2008 Jul 30 6:15 AM

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Hi Gurus,

Kindly tell me the basic performance techniques involved in developing an object.

Thanks in advance,

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Former Member

‎2008 Jul 30 7:43 AM

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614

Hi Rao,

The data traffic between the database server and the application server minimized by limiting fields selected by a proper WHERE clause and only to the fields actually needed?

Are SELECTu2026.ENDSELECT statements avoided by using INTO TABLE option?

Are nested SELECT statements avoided by using joins instead?

Are multiple SELECT SINGLE statements on the same database table avoided by using FOR ALL ENTRIES option?

If new entries must be added to internal table, are table rows added collectively via APPEND LINES instead of record-by-record?

If the table contents need to be changed, are table rows changed collectively by using INSERT/MODIFY/UPDATE FROM TABLE for custom database tables and MODIFY WHERE fro internal table instead of doing it record-by-record?

Has SQL trace been used in order to verify index use?

Hope this is helpful,

Thanks

Vijay Duvvada

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Former Member

‎2008 Jul 30 6:23 AM

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614

Hi,

Check these links-

http://searchsap.techtarget.com/searchSAP/downloads/May2006.pdf

Regards,

Sujit

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Former Member

‎2008 Jul 30 6:38 AM

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614

Hi,

Performance tuning

You need to consider below points to improve the performance of any program you write. Any one can write the program, but credit goes to

one who writes efficiently. Performance plays key role for reports, BDCs.

For all entries

Nested selects

Select using JOINS

Use the selection criteria

Use the aggregated functions

Select with view

Select with index support

Select u2026 Into table

Select with selection list

Key access to multiple lines

Copying internal tables

Modifying a set of lines

Deleting a sequence of lines

Linear search vs. binary

Comparison of internal tables

Modify selected components

Appending two internal tables

Deleting a set of lines

Tools available in SAP to pin-point a performance problem

Optimizing the load of the database

For all entries

The for all entries creates a where clause, where all the entries in the driver table are combined with OR. If the number of entries in the driver table is larger

than rsdb/max_blocking_factor, several similar SQL statements are executed to limit the length of the WHERE clause.

The plus

Large amount of data

Mixing processing and reading of data

Fast internal reprocessing of data

Fast

The Minus

Difficult to program/understand

Memory could be critical (use FREE or PACKAGE size)

Some steps that might make FOR ALL ENTRIES more efficient:

Removing duplicates from the the driver table

Sorting the driver table

If possible, convert the data in the driver table to ranges so a BETWEEN statement is used instead of and OR statement:

FOR ALL ENTRIES IN i_tab

WHERE mykey >= i_tab-low and

mykey <= i_tab-high.

Nested selects

The plus:

Small amount of data

Mixing processing and reading of data

Easy to code - and understand

The minus:

Large amount of data

when mixed processing isnu2019t needed

Performance killer no. 1

Select using JOINS

The plus

Very large amount of data

Similar to Nested selects - when the accesses are planned by the programmer

In some cases the fastest

Not so memory critical

The minus

Very difficult to program/understand

Mixing processing and reading of data not possible

Use the selection criteria

SELECT * FROM SBOOK.

CHECK: SBOOK-CARRID = 'LH' AND

SBOOK-CONNID = '0400'.

ENDSELECT.

SELECT * FROM SBOOK

WHERE CARRID = 'LH' AND

CONNID = '0400'.

ENDSELECT.

Use the aggregated functions

C4A = '000'.

SELECT * FROM T100

WHERE SPRSL = 'D' AND

ARBGB = '00'.

CHECK: T100-MSGNR > C4A.

C4A = T100-MSGNR.

ENDSELECT.

SELECT MAX( MSGNR ) FROM T100 INTO C4A

WHERE SPRSL = 'D' AND

ARBGB = '00'.

Select with view

SELECT * FROM DD01L

WHERE DOMNAME LIKE 'CHAR%'

AND AS4LOCAL = 'A'.

SELECT SINGLE * FROM DD01T

WHERE DOMNAME = DD01L-DOMNAME

AND AS4LOCAL = 'A'

AND AS4VERS = DD01L-AS4VERS

AND DDLANGUAGE = SY-LANGU.

ENDSELECT.

SELECT * FROM DD01V

WHERE DOMNAME LIKE 'CHAR%'

AND DDLANGUAGE = SY-LANGU.

ENDSELECT.

Select with index support

SELECT * FROM T100

WHERE ARBGB = '00'

AND MSGNR = '999'.

ENDSELECT.

SELECT * FROM T002.

SELECT * FROM T100

WHERE SPRSL = T002-SPRAS

AND ARBGB = '00'

AND MSGNR = '999'.

ENDSELECT.

ENDSELECT.

Select u2026 Into table

REFRESH X006.

SELECT * FROM T006 INTO X006.

APPEND X006.

ENDSELECT

SELECT * FROM T006 INTO TABLE X006.

Select with selection list

SELECT * FROM DD01L

WHERE DOMNAME LIKE 'CHAR%'

AND AS4LOCAL = 'A'.

ENDSELECT

SELECT DOMNAME FROM DD01L

INTO DD01L-DOMNAME

WHERE DOMNAME LIKE 'CHAR%'

AND AS4LOCAL = 'A'.

ENDSELECT

Key access to multiple lines

LOOP AT TAB.

CHECK TAB-K = KVAL.

" ...

ENDLOOP.

LOOP AT TAB WHERE K = KVAL.

" ...

ENDLOOP.

Copying internal tables

REFRESH TAB_DEST.

LOOP AT TAB_SRC INTO TAB_DEST.

APPEND TAB_DEST.

ENDLOOP.

TAB_DEST[] = TAB_SRC[].

Modifying a set of lines

LOOP AT TAB.

IF TAB-FLAG IS INITIAL.

TAB-FLAG = 'X'.

ENDIF.

MODIFY TAB.

ENDLOOP.

TAB-FLAG = 'X'.

MODIFY TAB TRANSPORTING FLAG

WHERE FLAG IS INITIAL.

Deleting a sequence of lines

DO 101 TIMES.

DELETE TAB_DEST INDEX 450.

ENDDO.

DELETE TAB_DEST FROM 450 TO 550.

Linear search vs. binary

READ TABLE TAB WITH KEY K = 'X'.

READ TABLE TAB WITH KEY K = 'X' BINARY SEARCH.

Comparison of internal tables

DESCRIBE TABLE: TAB1 LINES L1,

TAB2 LINES L2.

IF L1 <> L2.

TAB_DIFFERENT = 'X'.

ELSE.

TAB_DIFFERENT = SPACE.

LOOP AT TAB1.

READ TABLE TAB2 INDEX SY-TABIX.

IF TAB1 <> TAB2.

TAB_DIFFERENT = 'X'. EXIT.

ENDIF.

ENDLOOP.

ENDIF.

IF TAB_DIFFERENT = SPACE.

" ...

ENDIF.

IF TAB1[] = TAB2[].

" ...

ENDIF.

Modify selected components

LOOP AT TAB.

TAB-DATE = SY-DATUM.

MODIFY TAB.

ENDLOOP.

WA-DATE = SY-DATUM.

LOOP AT TAB.

MODIFY TAB FROM WA TRANSPORTING DATE.

ENDLOOP.

Appending two internal tables

LOOP AT TAB_SRC.

APPEND TAB_SRC TO TAB_DEST.

ENDLOOP

APPEND LINES OF TAB_SRC TO TAB_DEST.

Deleting a set of lines

LOOP AT TAB_DEST WHERE K = KVAL.

DELETE TAB_DEST.

ENDLOOP

DELETE TAB_DEST WHERE K = KVAL.

Tools available in SAP to pin-point a performance problem

The runtime analysis (SE30)

SQL Trace (ST05)

Tips and Tricks tool

The performance database

Optimizing the load of the database

Using table buffering

Using buffered tables improves the performance considerably. Note that in some cases a stament can not be used with a buffered table, so when using

these staments the buffer will be bypassed. These staments are:

Select DISTINCT

ORDER BY / GROUP BY / HAVING clause

Any WHERE clasuse that contains a subquery or IS NULL expression

JOIN s

A SELECT... FOR UPDATE

If you wnat to explicitly bypass the bufer, use the BYPASS BUFFER addition to the SELECR clause.

Use the ABAP SORT Clause Instead of ORDER BY

The ORDER BY clause is executed on the database server while the ABAP SORT statement is executed on the application server. The datbase server will

usually be the bottleneck, so sometimes it is better to move thje sort from the datsbase server to the application server.

If you are not sorting by the primary key ( E.g. using the ORDER BY PRIMARY key statement) but are sorting by another key, it could be better to use the

ABAP SORT stament to sort the data in an internal table. Note however that for very large result sets it might not be a feasible solution and you would want

to let the datbase server sort it.

Avoid ther SELECT DISTINCT Statement

As with the ORDER BY clause it could be better to avoid using SELECT DISTINCT, if some of the fields are not part of an index. Instead use ABAP SORT +

DELETE ADJACENT DUPLICATES on an internal table, to delete duplciate rows.

Reward Points if useful

Raghunath.S

9986076729

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Former Member

‎2008 Jul 30 7:43 AM

0 Likes
615

Hi Rao,

The data traffic between the database server and the application server minimized by limiting fields selected by a proper WHERE clause and only to the fields actually needed?

Are SELECTu2026.ENDSELECT statements avoided by using INTO TABLE option?

Are nested SELECT statements avoided by using joins instead?

Are multiple SELECT SINGLE statements on the same database table avoided by using FOR ALL ENTRIES option?

If new entries must be added to internal table, are table rows added collectively via APPEND LINES instead of record-by-record?

If the table contents need to be changed, are table rows changed collectively by using INSERT/MODIFY/UPDATE FROM TABLE for custom database tables and MODIFY WHERE fro internal table instead of doing it record-by-record?

Has SQL trace been used in order to verify index use?

Hope this is helpful,

Thanks

Vijay Duvvada