Understanding SQR Performance and SQL Statements

Whenever a program contains a BEGIN-SELECT, BEGIN-SQL, or EXECUTE command, it performs a SQL statement. Processing SQL statements typically consumes significant computing resources. Tuning SQL statements typically yields higher performance gains than tuning any other part of the program.

General tuning of SQL is outside the scope of this PeopleBook because tuning SQL is often specific to the type of database that you are using: tuning SQL statements for an Oracle database may be different from tuning SQL statements for DB2. This topic focuses on SQR tools for simplifying SQL statements and reducing the number of times SQL is run.