Factors that Influence the Processing of an SQL Statement (SAP Library

Factors that Influence the Processing of an SQL Statement

The following factors play a role during the processing of an SQL statement:

Type of physical storage of a table

Size of the tables (Number of lines and B* tree pages)

Definition of the table (especially the key columns)

Definition of indexes

Type of SQL statement (SELECT, INSERT, UPDATE, DELETE)

Elements of a SELECT statement (ORDER clause, UPDATE clause, DISTINCT specification, and specification of FOR REUSE)

Changes that are specified in the UPDATE statement

Search conditions

These factors especially influence the processing of an SQL statement if the SQL statement triggers a search of a large quantity of data. This generally happens with the following SQL statements:

SELECT ...
INSERT ... SELECT ...
UPDATE ... WHERE <search_condition>
DELETE ... WHERE <search_condition>