Tips for Using Oracle Stored Procedures

Oracle stored procedures and triggers are faster than traditional code, which means they are becoming increasingly popular. As application code moves away from external programs and into the database engine, DBAs need to understand the related memory requirements for Oracle stored procedures and know how to manage stored procedures for optimal database performance.

Oracle stored procedures and triggers are becoming more popular, and more application code will move away from external programs and into the database engine. Oracle DBAs must be conscious of the increasing memory demands of Oracle stored procedures, however, and carefully plan for the days when all of the database access code (PL/SQL) resides within the database. Today, most Oracle Server databases have only a small amount of code in stored procedures, but this is rapidly changing. There are many compelling benefits to putting all Oracle SQL inside stored procedures, including:


Better performance.
Oracle stored procedures load once into the shared pool and remain there unless they become paged out. Subsequent executions of the stored procedure are far faster than executions of external code.

Coupling of data with behavior.
DBAs can use naming conventions to couple relational tables with the behaviors associated with a table (using Oracle stored procedures as "methods"). If all behaviors associated with the employee table are prefixed with the table name--employee.hire, employee.give_raise, for example--the data dictionary can be queries to list all behaviors associated with a table (select * from dba_objects where owner = 'EMPLOYEE'), and it's easy to identify and reuse code.

Isolation of code.
Since all SQL is moved out of the external programs and into the Oracle stored procedures, the application programs become nothing more than calls to stored procedures. As such, it becomes very simple to swap out one database and swap in another one.

One of the foremost reasons stored procedures and triggers function faster than traditional code is related to caching in the Oracle SGA. After an Oracle stored procedure has been loaded into the shared pool of the SGA, it remains there until it is paged out of memory to make room for other stored procedures. Items are paged out based on a least recently used (LRU) algorithm. Once loaded into the RAM memory of the shared pool, procedures will execute very quickly, and the trick is to prevent pool thrashing as many procedures compete for a limited amount of shared-pool memory.

Source www.rampant-books.com