Use serially reusable packages - performance of application, PL-SQL Programming

Use Serially Reusable Packages

To help you to manage the use of memory, the PL/SQL gives the pragma SERIALLY_ REUSABLE that mark some packages as serially reusable. So mark a package if its state is required only for the duration of one call to the server (for illustration, an OCI call to the server or a server-to-server RPC).

The global memory for these packages is pooled in the System Global Area (SGA), not allocated to the individual users in the User Global Area (UGA). In that way, the package work region can be reused. If the call to the server ends, the memory is return to the pool. Each time the package is reused, the public variables are initialized to its default values or to NULL.

The maximum number of work regions required for a package is the number of concurrent users of that package that is usually much smaller than the number of logged-on users. The bigger use of SGA memory is more than offset by the reduced use of UGA memory. The Oracle ages-out work areas are also not in use if it requires reclaiming the SGA memory.

For packages without a body, you code the pragma in the package specification using the

Syntax as shown:

PRAGMA SERIALLY_REUSABLE;

For packages with a body, you should code the pragma in the specification and body. You cannot only code the pragma in the body. The illustration below shows how a public variable in a serially reusable package behaves across the call boundaries:

CREATE OR REPLACE PACKAGE sr_pkg IS

PRAGMA SERIALLY_REUSABLE;

num NUMBER := 0;

PROCEDURE init_pkg_state(n NUMBER);

PROCEDURE print_pkg_state;

END sr_pkg;

/

CREATE OR REPLACE PACKAGE BODY sr_pkg IS

PRAGMA SERIALLY_REUSABLE;

/* Initialize package state. */

PROCEDURE init_pkg_state (n NUMBER) IS

BEGIN

sr_pkg.num := n;

END;

/* Print package state. */

PROCEDURE print_pkg_state IS

BEGIN

DBMS_OUTPUT.PUT_LINE('Num is: ' || sr_pkg.num);

END;

END sr_pkg;

/

BEGIN

/* Initialize package state. */

sr_pkg.init_pkg_state(4);

/* On same server call, print package state. */

sr_pkg.print_pkg_state; -- prints 4

END;

/

-- subsequent server call

BEGIN

-- package's public variable will initialized to its

-- default value automatically

sr_pkg.print_pkg_state; -- prints 0

END;

Posted Date: 10/5/2012 4:59:55 AM | Location : United States







Related Discussions:- Use serially reusable packages - performance of application, Assignment Help, Ask Question on Use serially reusable packages - performance of application, Get Answer, Expert's Help, Use serially reusable packages - performance of application Discussions

Write discussion on Use serially reusable packages - performance of application
Your posts are moderated
Related Questions
Challenge 1 You are required to do the project and write a test plan for it. Demo 4 is a check writer program for employees. In it, the user enters all information about the

Fetching from a Cursor Variable The FETCH statement retrieve rows one at a time from the product set of a multi-row query. The syntax for the same is as shown: FETCH {curso

I need SQL Data Base Project Description: Network SQL database and SQL Setup two 4 workstation Skills required are Data Entry, MySQL, SQL

Role of Abstraction in pl/sql: The abstraction is a high-level description or model of a real-world entity. The Abstractions keep our daily lives convenient. They help us ca

Disjunction (OR, ∨) Again we have nine rows instead of just four and again, when unknown is not involved, the rows are as for 2VL. Also, when anything is paired with true, t

Error Handling The PL/SQL makes it easy to detect and process the predefined and user-defined error conditions known as exceptions. Whenever an error occurs, an exception is ra

Declaring Cursor Variables Once a REF CURSOR type is define by you, and then you can declare the cursor variables of that type in any PL/SQL block or subprogram. In the exampl

Running the PL/SQL Wrapper To run the PL/SQL Wrapper, go through the wrap command at your operating system prompt by using the syntax as shown: wrap iname=input_file [oname=

Inner Join We have learned how to retrieve data from one table by using SELECT statement. But, as we have learned, normalized relational databases mean the data is spread betw

what is the use of declare keyword