topic Re: Indexes in Application Development and Automation Discussions

Indexes

Former Member — Wed, 14 May 2008 04:44:01 GMT

1) How can we check the performance of the created secondary index ?

2) How can we check the performance of the ABAP Program ?

3) What is the Cost Based Optimizer ?

Re: Indexes

Sm1tje — Wed, 14 May 2008 04:50:52 GMT

1/2. In transaction ST05, you can check if index is used. And in SE30 you can check the overall performance.

3. This is database optimizer which will select best index for selections.

The parameter optimizer_mode is set for SAP systems and should only be changed if recommended by SAP. You should also take into account the appropriate notes.

In contrast to the rule-based optimizer, you should create statistical tables for the cost-based optimizer. If you do not regularly create these table statistics, this may cause the cost-based optimizer to make wrong decisions and result in performance problems.

Edited by: Micky Oestreich on May 14, 2008 6:53 AM

Re: Indexes

Former Member — Wed, 14 May 2008 04:53:58 GMT

Performance Tuning

https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/5d0db4c9-0e01-0010-b68f-9b1408d5f234

http://www.sap-img.com/abap/performance-tuning-for-data-selection-statement.htm

http://www.thespot4sap.com/Articles/SAPABAPPerformanceTuning_PerformanceAnalysisTools.asp

https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/abapPerformanceand+Tuning&

http://www.erpgenie.com/abap/performance.htm

http://www.sap-img.com/abap/performance-tuning-for-data-selection-statement.htm

https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/abapPerformanceand+Tuning&

http://help.sap.com/saphelp_nw2004s/helpdata/en/c6/617cafe68c11d2b2ab080009b43351/frameset.htm

http://help.sap.com/saphelp_nw2004s/helpdata/en/d1/801f7c454211d189710000e8322d00/frameset.htm

Regards,

Santosh

Re: Indexes

Former Member — Wed, 14 May 2008 05:02:41 GMT

Hi,

2. Run Time Analyser

http://help.sap.com/saphelp_47x200/helpdata/en/c6/617cafe68c11d2b2ab080009b43351/content.htm

3. SQL trace

http://help.sap.com/saphelp_47x200/helpdata/en/d1/801f7c454211d189710000e8322d00/content.htm

Regards

Kiran Sure

Re: Indexes

Former Member — Wed, 14 May 2008 14:00:43 GMT

2--> To check the performence of a ABAP Program

Goto Program on the toolbar in the report screen then navigate as follows program~~->check~~> extended program check and code inspector .

These provides the performence trace.

3--->In detail about Optimerzers and Cost based optimizer

The Optimizer

Each database system uses an optimizer whose task is to create the execution plan for SQL statements (for example, to determine whether to use an index or table scan). There are two kinds of optimizers:

Rule based

Rule based optimizers analyze the structure of an SQL statement (mainly the SELECT and WHERE clauses without their values) and the table index or indexes. They then use an algorithm to work out which method to use to execute the statement.

Cost based

Cost based optimizers use the above procedure, but also analyze some of the values in the WHERE clause and the table statistics. The statistics contain low and high values of the fields, or a histogram containing the distribution of data in the table. Since the cost based optimizer uses more information about the table, it usually leads to faster database access. Its disadvantage is that the statistics have to be periodically updated.

Use

ORACLE databases up to and including release 7.1 use a rule-based optimizer. As of Release 7.2 (SAP Release 4.0A), they use a cost-based optimizer. All other database systems use a cost-based optimizer.

Re: Indexes

Former Member — Tue, 15 Jul 2008 03:48:21 GMT

I Myself solved the issue.