How to use multiple concurrent contexts

Question

I have a context package that uses a session_id. I want to use multiple sessions as I will have multiple users creating contexts at the same time. Once the context is created with a session_id I want to reference that session_id in a view. Can this be done?
Using Oracle 10g R2
Context:
-- create ctx
CREATE OR REPLACE CONTEXT MY_CTX USING CTX_PKG
ACCESSED GLOBALLY;
-- ctx package
  CREATE OR REPLACE PACKAGE CTX_PKG
IS
   PROCEDURE SET_SESSION_ID (IN_SESSION_ID VARCHAR2);
   PROCEDURE CLEAR_SESSION (IN_SESSION_ID VARCHAR2);
   PROCEDURE SET_CONTEXT(IN_NAME VARCHAR2, IN_VALUE VARCHAR2);
END CTX_PKG;
-- context packatge
  CREATE OR REPLACE PACKAGE BODY CTX_PKG
IS
   GC$SESSION_ID  VARCHAR2 (100);
   PROCEDURE SET_SESSION_ID (IN_SESSION_ID VARCHAR2)
   IS
   BEGIN
    GC$SESSION_ID := IN_SESSION_ID;
    DBMS_SESSION.SET_IDENTIFIER (IN_SESSION_ID);
  END;
   PROCEDURE CLEAR_SESSION (IN_SESSION_ID VARCHAR2)
   IS
   BEGIN
    DBMS_SESSION.SET_IDENTIFIER (IN_SESSION_ID);
    DBMS_SESSION.CLEAR_IDENTIFIER;
   END;
   PROCEDURE SET_CONTEXT (IN_NAME VARCHAR2, IN_VALUE VARCHAR2)
   IS
   BEGIN
    DBMS_SESSION.SET_CONTEXT ('MY_CTX',
                 IN_NAME,
                 IN_VALUE,
                 USER,
                 GC$SESSION_ID);
   END;
END CTX_PKG;
Create context values:
begin
ctx_pkg.set_session_id ('222');
ctx_pkg.set_context ('valoc','53,89');
ctx_pkg.set_context('fromdate','10/01/2007');
ctx_pkg.set_context('todate','09/30/2013');
end;
Extract values:
select sys_context('my_ctx','valoc') from dual
select sys_context('my_ctx','gc$session_id') from dual
The first query returns valoc but the second query doesn't return the session_id.

Answer 1

Hi,
If you want each session to have its own private set of values, then omit "ACCESSED GLOBALLY" when you create the context:
CREATE OR REPLACE CONTEXT MY_CTX USING CTX_PKG
Anyone using a context like this will only see the values that were entered in his own session.  There's nothing you, as the application developer, need to do to distinguish one session from another.
You can use this in parameterized views.
With the change I posted before, I can do things like:
select  sys_context ('my_ctx', 'valoc')
from    dual
where   sys_context ('my_ctx','gc$session_id') = '222';
What are you doing differently?  You said, "I'm still not getting a return for gc#session_id."  Does that mean you're misspelling the name, using  '$' to set the variable and '#' when you try to retrieve it?
As always, post a complete test script that people can run to re-create the problem and test their ideas. Copy and edit your original message; you probably only need to change a couple of lines.
There is no built-in realtion between the different items in a namespace.  The query immediately above is conceptually no different from
SELECT  :valloc
FROM    dual
WHERE   :gc$session_id = '222';
or
SELECT  '&valloc'
FROM    dual
WHERE   '&gc_session_id' = '222';
where the item in the SELECT clause and the first item in the WHERE clause are any kind of variables.  SYS_CONTEXT is just another way of handling variables.