ST04-SQL Request

Question

Hi Friends,
In my production system, I've executed the ST04 transaction, Detailed Analysis Menu....SQL Request....Sorted by Buffer gets... and I checked the SQL statement....and then clicked on display execution plan for SQL statement...
There it shows the following information
SELECT STATEMENT ( Estimated Costs = 17,039 , Estimated #Rows = 0 )
        1 TABLE ACCESS FULL LIPS
          ( Estim. Costs = 17,038 , Estim. #Rows = 1 )
          Estim. CPU-Costs = 885,646,245 Estim. IO-Costs = 16,963
          Filter Predicates
What are the parameters that will indicate that there is an issue with the SQL statement
Regards
Aliila

Answer 1

Hello Aliila,
As indicated below, the statement is expensive as the explain plan goes for full table scan. As LIPS table is one of the line item table, it has to read all the blocks of this table to satisfy the user query. So if there is no WHERE clause in the corresponding ABAP code, then you have to discuss with your ABAP developer to input the selective fields in the WHERE clasue so that appropriate indexes will be choosen in the explain plan. From this i can easily conclude that this statment is expensive because of either of these reasons.
1. Missing Where clause in the ABAP code ( I believe this is coming from Z* program/transaction) or
2. User is not inputting any criteria for selecting this ( Here you to need to train the user).
Back to your question: if you are doing sql cache analysis through ST04 normally you have to find out the statement based on the following criteria.
1. Greater than 5% of  the total buffer gets ( This will cause memory load)
and/or
2. Greater than 2% of the physcial reads ( This cause I/O Load).
you can find that total buffers gets and physical read from ST04 initial screen.
Hope above information will help you.
Yours Sincerely
Dileep