Administering data access applications

These administrative tasks consist primarily of configuring the objects, or resources, through which applications connect with a backend, and tuning those resources to handle the volume of connection requests.

Procedure

  1. If your application contains Web modules or EJB modules that require access to a backend, configure resources according to your type of enterprise information system (EIS):
    • For a relational database, follow the steps outlined in the topic, Configuring a JDBC provider and data source. If you are using a DB2® database, the topic, Configuring an application to use pureQuery is another option. PureQuery provides an alternative to JDBC as a way to access the DB2 database.
    • For a non-relational database, or another type of EIS such as the Customer Information Control System (CICS®), you must configure a resource adapter and connection factories. The topic, Accessing data using Java EE Connector Architecture connectors, provides information on setting up these objects.
    Avoid trouble: When you specify the Java™ Naming and Directory Interface (JNDI) name for resources, adhere to the following requirements:
    • Do not assign duplicate JNDI names across different resource types (such as data sources versus J2C connection factories or JMS connection factories).
    • Do not assign duplicate JNDI names for multiple resources of the same type in the same scope.
    gotcha
  2. Configure an authentication alias for the new Web module resource or EJB module resource only if the application code, rather than WebSphere® Application Server, authenticates connections with the backend. This security configuration is called component-managed authorization, and is indicated in the application deployment descriptor as res-auth = Application.

    Container-managed authorization, which is designated as res-auth = Container, indicates that Application Server performs signon for backend connections. The container-managed authentication alias must be specified on the application resource reference. This task can be done during application assembly or deployment, along with mapping the resource reference to a data source or connection factory resource. After application deployment, however, you can alter the container-managed authentication alias using the administrative console. Click Applications > Websphere enterprise applications > application_name , and select the link to the appropriate mapping page. For example, if you want to alter the alias of an EJB module resource, you might click Map data sources for all 2.x CMP beans. For a Web module resource, click Resource References.

    Read the J2EE connector security topic for detailed reference on resource authentication.

  3. If your application contains a client module that requires data access, see the topic, Configuring data access for application clients. In this single configuration process, you can define authentication data for either component-managed or container-managed signon.
  4. Specify connection pool settings.
  5. Test a connection to the new data source. See the article, Test connection service, for information on the available methods for testing connections. This article also addresses important data source settings that can affect the accuracy of your test connection results.
  6. Set the JDBC trace service. The JDBC trace log information augments the JVM log data for data source failures.

    To activate the trace using the administrative console, read the topic, Enabling trace at server startup.. Specify WAS.database as the trace group and select com.ibm.ws.db2.logwriter as the trace string.

  7. Gather connection pool statistics by activating the JDBC connection pool counters or the J2C connection pool counters. Alternatively, you can use Performance Monitoring Infrastructure (PMI) method calls to gather connection statistics; see the topic, Connection and connection pool statistics.
  8. [AIX Solaris HP-UX Linux Windows] [z/OS] Tune the resources to manage connection volume. See the topic, Data access tuning parameters.
  9. [iSeries] Tune your database to accommodate the connection volume. If you use DB2 UDB for iSeries™, see the topic, DB2 Universal Database performance tips, as a starting point reference.

Results [z/OS]

If your z/OS® application connects to a z/OS version of DB2 that serves multiple platform versions of WebSphere Application Server, the z/OS application might incur an EC3 dump during run time. To resolve the problem, set the CMTSTAT parameter to INACTIVE when you plan to run distributed workloads.
Avoid trouble: For DB2 Version 7.0 on a z/OS system, the default value for CMTSTAT is ACTIVE. For DB2 Version 8.0 on a z/OS system, the default setting is set to INACTIVE.gotcha
Distributed workloads are generally large. The CMTSTAT=INACTIVE setting triggers DB2 to free up resources to counteract the drain that can be caused by large workloads. DB2 will deactivate threads after the threads successfully commit or roll back database tasks and release cursors.
If you set CMTSTAT=INACTIVE, you might need to adjust the CONDBAT and MAXDBAT parameters as well. Try the following combination of values to maximize the performance of DB2 and minimize suspended connection requests:
  • Set MAXDBAT to a low number, like 100, which DB2 can support as active threads. MAXDBAT indicates the maximum number of threads that can remain active at the same time and continue running tasks in DB2.
  • Set CONDBAT to a high number, like 5000. CONDBAT indicates the maximum number of connection request threads that your DB2 server can receive. When you set CMTSTAT to INACTIVE, DB2 will deactivate many threads after fulfilling the initial connection requests. When the number of threads that require further processing reaches the MAXDBAT setting, DB2 can queue other threads until it can handle them.



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Last updated: Oct 21, 2010 10:04:34 PM CDT
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