Oracle Application server connection pool and database links

Question

I am using Oracle application server 10g with connection pools, the db used by the application connects to another oracle db using a database link. My question is when the application starts it creates 10 connections, does it also create x amount of database links as well?

Answer 1

Hi,
Is there any way to use the connection pool or Datasource while connecting to database?If I am using a stateless sesssion bean and using a Data Access layer which just creates a database session to write the persistence toplink objects how I can make use of application server connection pool?Hi Vinod,
Yes, TopLink allows you to use the app server's connection pooling and transaction services. Chapter 2 of the Oracle9iAS TopLink Foundation Library Guide provides details as do the TopLink examples. The easiest way to set this up is by using the sessions.xml file. The sample XML below is from the file <toplink903>\examples\ias\examples\ejb\sessionbean\sessions.xml. Here we are adding the datasource defined in OC4J and specifying that we are using the OC4J transaction controller also.
<login>
<user-name>sa</user-name>
<password></password>
<datasource>java:comp/env/jdbc/ejbJTSDataSource</datasource>
<uses-external-transaction-controller>true</uses-external-transaction-controller>
<uses-external-connection-pool>true</uses-external-connection-pool>
</login>
<external-transaction-controller-class>oracle.toplink.jts.oracle9i.Oracle9iJTSExternalTransactionController</external-transaction-controller-class>
When using this approach you need to change your TopLink code slightly in the EJB methods:
a. Acquire the ACTIVE unit of work from the server
session (again, see the EmployeeSessionEJB code
example) with something like:
UnitOfWork uow = clientSession.getActiveUnitOfWork();
b. Calls to uow.commit() can be ommitted or commented out
because the EJB will handle this. Note that of course
the methods you create in the EJB that are using this
approach must have TX Required (default).
Hope this helps.
Pete