What about session memory when using BEA Weblogic connection pooling?

Question

Hi,
consider a web application, allowing database connections via a BEA Weblogic 8.1 application server. The app-server is pooling the oracle connections. The oracle database is running in dedicated server mode.
How are the database requests from the web app served by the connection pool from BEA?
1) Does one oracle session serve more than one request simultanously?
2) Does BEA serialize the requests, which means, that a session from the pool is always serving only one request at a time?
If (1) is true, than what about the session memory of Oracle sessions? I understand, that things like package global variables are beeing stored in this session private memory. If (1) is true, the PL/SQL programmer has the same situation, as with programming an Oracle databas in "shared server" mode, that is, he should not use package global variables etc.
Thankful for any ideas...
Message was edited by:
Xenofon

Answer 1

Xenofon Grigoriadis wrote:
Hi,
consider a web application, using BEA between client and an Oracle Database (v9i). BEA is pooling the oracle connections. The oracle database is running in dedicated server mode.
How are the database requests from the web app beeing served by the connection pool from BEA?
1) Does one oracle session serve more than one request simultanously?no.
2) Or does BEA serialize the requests, which means, that a session from the pool is always serving only one request at a time?
Reading "Configuring and Using WebLogic JDBC" from weblogic8.1 documentation, I read:
"... Your application "borrows" a connection from the pool, uses it, then returns it to the pool by closing it...."
What do you mean by returning the connection by closing it? Tbe server will either return the connection to the pool or close it...When application code does typical jdbc code, it obtains
a connection via a WebLogic DataSource, which reserves an
unused pooled connection and passes it (transparently wrapped)
to the application. The application uses it, and then closes
it. WebLogic intercepts the close() call via the wrapper, and
puts the DBMS connection back into the WebLogic pool.
The reason, why I as an Oracle programmer ask this is, because every session (=connection)
in Oracle has its own dedicate, private memory for things like global PL/SQL variables.
Now I want to figure out, if you have to careful in programming your databases, when
one Oracle session (=connection) is serving many weblogic requests.It is serving many requests, but always serially. Do note however, that we
also transparently cache/pool prepared and callable statements with the
connection so repeat uses of the connection will be able to get already-made
statements when they call prepareStatement() and prepareCall(). These
long-lived statements will each require a DBMS-side cursor.
>
Thankful for any ideas or practical experience...
Message was edited by:
mk637Joe