Size Category & performance

[Former Member]

Dear All,

I like to know is there any relation ship between the size category of a tables and performance when the same table is used in report.

table LTAK(Header table) is having size category 4 Data records expected 130000-10000000

table LTAP(item table) is having size category 2 Data records expected 3100 – 12000

in my case Item table contains around 2838000 records and header table contains 929000 records so because of size category my performance will be low ?

I am using SELECT * clause and "FOR ALL ENTRIES" clause

thanks & best regards

Vinayak

[Former Member]

Hi Vinayak ,

This the explanation of size category which I pasted from SAP.

<i>The size category determines the probable space requirement for a table in the database.

You can select the categories 0 to 4 for your table. Each category is assigned a specific fixed storage area value in the database. When you create a table, initial space is saved for it in the database. If more space is required later as a result of data that has been entered, the storage space is increased in accordance with the category selected.

Press F4 on the field Size category to see the number of data records that can be maintained for the individual categories of your table without complications ensuing. These complications could be for example a reorganization becoming necessary because the maximum space to be reserved for the table was exceeded due to the maintained size category.

</i>

Your codes performance ( generally ) will depend on your Select statement .

For example if you don' t use proper where statement , the performance will be low, you want to fetch huge amount of data & if you want all fields of table it will be bad also.

Regards,

Caglar

Message was edited by:

Caglar Ozkor

[Former Member]

Hi Caglar,

Will please explain me what do you mean by proper where statement. Also if you can give me some performance tips on ABAP Trace & SQL Trace I will be very thankful to you.

Thanks

Vinayak

[Former Member]

Hi

WHERE statement:

1. dont use logical operators like <> , this will sideline the index search. it will do a full table scan.

2. try to use the primary keys, if not secondary index atleast.

SE30(Runtime analysis):

using this u can find which part of the program is taking more time...say ABAP, SQL or system.

this will give the percentage of execution time category wise.

then in the basic screen of se30 u can find a tab 'tips & tricks'. there you can find more details..

u can compare the performance of 2 codes.

ST05:

sql trace tool.

1. activate trace

2. execute your program

3. deactivate trace

4. display trace

5. In menu bar --> Trace list

you can see indivudual's select performance ( Summarise by SQL statements)

and the table usage ( summarise by tables)

and accordingly modify the program.

For more details you can check this link:

https://www.sdn.sap.com/irj/sdn/wiki?path=/display/home/abap%2bperformance%2band%2btuning

regards,

madhu

[Former Member]

Hi Vinayak,

For performance tuning please check these threads , you' ll find good documentations.

And also please check these weblogs ;

<a href="/people/rob.burbank/blog/2006/09/13/using-an-index-when-you-dont-have-all-of-the-fields">/people/rob.burbank/blog/2006/09/13/using-an-index-when-you-dont-have-all-of-the-fields</a>

<a href="/people/rob.burbank/blog/2006/02/07/performance-of-nested-loops:///people/rob.burbank/blog/2006/02/07/performance-of-nested-loops

<a href="/people/rob.burbank/blog/2006/11/16/performance--what-will-kill-you-and-what-will-leave-you-with-only-a-flesh-wound">/people/rob.burbank/blog/2006/11/16/performance--what-will-kill-you-and-what-will-leave-you-with-only-a-flesh-wound</a>

<a href="/people/rob.burbank/blog/2006/11/16/performance--what-will-kill-you-and-what-will-leave-you-with-only-a-flesh-wound">/people/rob.burbank/blog/2006/11/16/performance--what-will-kill-you-and-what-will-leave-you-with-only-a-flesh-wound</a>

Hope this helps,

Kind Regards

Caglar

[Former Member]

hi

it jus gives the capacity of the table n the maximum records the table can hold.

the performance of the select depends on the current size of the table in ur system.

the select will perform better if you are using the primary keys.

it is better to select only the required fields.

when using for all entries chk the following:

1. sort the table with required fields.

2. delete the duplicate entries comparing the fields.

3. chk if the internal table is initial.

regards,

madhu

[Former Member]

HI,

Its better u check in your program, hit all the key fields and better to use binary search for all read statements. it will make a lot of difference when u use sort and binary search. avoid nested loops and use while, endwhile.

[alison_lloyd]

size category has more to do with general database performance/sizing. Program performance depends on how you select the data from the tables - use st05 for db accesses, se30 to see tips and tricks and check if code or dba ccess

[alison_lloyd]

size category has more to do with general database performance/sizing. Program performance depends on how you select the data from the tables - use st05 for db accesses, se30 to see tips and tricks and check if code or dba ccess