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
Parameter Aliasing   To optimize the subprogram call, the PL/SQL compiler can decide between the two techniques of the parameter passing. With the by-value techniques, the v

Usefulness of Data Type In SQL, as in most computer languages, a type can be used for constraining the values that are permitted to be used for some purpose. In particular, i

Use Object Types and Collections The Collection types and object types increase your efficiency by allowing for the realistic data modeling. The Complex real-world entities an

PRIMARY KEY: PRIMARY KEY  indicates that the table is subject to a key constraint, in this case declaring that no two rows in the table assigned to ENROLMENT can ever have the

Keyword and Parameter Description: boolean_expression: This is an expression which results the Boolean value TRUE, FALSE, & NULL. It is related with a series of statement

Projection and Existential Quantification - SQL Intuitively it might seem that projection in SQL is simply a matter of specifying the required columns in the SELECT clause, a

Committing and Rolling Back The COMMIT and ROLLBACK end the active autonomous transaction but do not exit the autonomous routine. As the figure shows, if one transaction ends,

Change Sql file into CSV for product registration on Magento Project Description: I have a set of files that are in Sql format and could like for a developer to help me with

what is the use of declare keyword

Obtaining a natural join by specifying the common columns Synatax: SELECT * FROM IS_CALLED JOIN IS_ENROLLED_ON USING ( StudentId ) However, a named columns join doe