Managing literal values in PL/SQL

Question

Running on Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production With the Partitioning and OLAP options JServer Release 9.2.0.8.0 - Production
We need to manipulate some specific values at runtime, and decided on storing these in a table. Our PL/SQL code retrieves these values to use in various queries etc... such as limit a cursor to a certain number of rows, or change some constant in a package etc.
I've looked into Steven Feuerstein's best practices site with regards to managing "magic values" in PL/SQL. We've implemented a solution as per his column: http://apex.oracle.com/pls/otn/f?p=2853:4:271093498565934::NO::P4_QA_ID:16382
Basically a table holder our "literal" value data, with a packaged function to retrieve a given value by its name from another PL/SQL package.
Now to avoid multiple calls to literal value get functions, I create a private global variable in the package body, and retrieve the given literal value into it. I then re-use this global variable throughout the pacakge body.
For instance:
g_bulk_mailer_email            VARCHAR2 (255)
      := pkg_application_constant.varchar2_value ('BULK_MAILER_EMAIL_ADDRESS');The problem I'm facing is, when I change the literal value BULK_MAILER_EMAIL_ADDRESS, in the database table, it doesn't apply to my global variable g_bulk_mailer_email in my package body. I assume because the package is already initialized and pinned in the UGA?
Is this a case for the SERIALLY_REUSABLE pragma, or bad implementation/design on my part?
The one alternative I thought of is to simply not use the global variable, and simply make multiple local calls where needed in my package subprograms, so it always gets the latest values from the literal value table.
p.s. Once we migrate to 11g, I plan on using the result function cache...
Thanks for any tips/advice
Stephane

Answer 1

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The problem I'm facing is, when I change the literal value BULK_MAILER_EMAIL_ADDRESS, in the database table, it doesn't apply to my global variable g_bulk_mailer_email in my package body. I assume because the package is already initialized and pinned in the UGA?Highly likely so. One way can be to reinitilize the package variable. But this works only if you change the database value inside the same session. Other sessions would not be effected.
There should be others ways to
Flushing the shared pool would probably work, but should not be done because it harms the overall performance of your system more than it helps. THere could be a way to invalidate the package. But then the next access from each session would get an error (invalid package state) and the second access to it would reload all.
The one alternative I thought of is to simply not use the global variable, and simply make multiple local calls where needed in my package subprograms, so it always gets the latest values from the literal value table.It is a tradeoff between performance and accuracy. But if the literal value table is pinned to the SGA, then oracle will take care of optimizing the access to it. This doesn't mean that you approach is badly designed. Just that there are different things to consider.