Implicitly set client information

If we track client information in the database, we can choose one of two ways to pass WebSphere Application Server client data on database connections.

We can choose to explicitly pass the information about connections by calling an IBM proprietary API, setClientInformation(Properties), on the com.ibm.websphere.rsadapter.WSConnection object within the application code. The com.ibm.websphere.rsadapter.WSConnection object is located in the plugins_root/com.ibm.ws.runtime.jar file. In some cases, however, you might want WebSphere Application Server to handle the passing of client information to database connections. This method of setting the client information is referred to as implicit. We might choose the implicit method because:

• You want to keep the application free of proprietary APIs, or

• Your application uses container-managed persistence (CMP), in which case we cannot use the proprietary API to set client information on database connections.

The WebSphere Application Server trace facility provides the capability for setting client information implicitly. We can designate one of two special trace groups to enable or disable client information passing: WAS.clientinfo trace or WAS.clientinfopluslogging trace.

Possible runtime scenarios

• Connection sharing

  In the case of connection sharing, WebSphere Application Server sets the client information on the first acquired connection handle only. If connection sharing is enabled and two or more getConnection methods are called (resulting in two handles on the same connection), only the first getConnection call causes the client information to pass to the backend database. This scenario does not apply to the explicit process of passing client information; in such cases every setClientInformation method is relayed to the database regardless of connection sharing.

• Implicit/explicit co-existence

  When you use both the explicit and implicit procedures for relaying client information, some combination of the explicitly set data and implicitly set data is combined, but the explicit setting usually takes precedence. For example, if the application sets the client accounting information to "myAccountingInfo", the final accountingInfo string that is passed to the backend database looks something like the following sample code:

  000325_WSRdbManagedConnectionImpl@1234_myAccountingInfo:

  Where 000325 is the thread ID and WSRdbManagedConnectionImpl@1234 is the WebSphere connection instance.

• Client information reset

  When you configure Application Server to pass client information, it does reset client information when a connection is returned to the pool, but only if the WAS.clientinfo and WAS.clientinfopluslogging trace mechanisms are disabled (that is, WAS.clientinfo=all=disabled:WAS.clientinfopluslogging=all=disabled).

  In the explicit case, however, the reset operation is done only when the application issues setClientInformation(null) on the WSConnection connection.

WAS.clientinfo trace

By default, the implicit mechanism is disabled. We can turn on this mechanism dynamically, without stopping and starting the application server, or statically by setting the WAS trace group WAS.clientinfo=all=enabled.

The information implicitly collected and set on the database connection consists of the user name, user location and application name.

(zos) The information implicitly collected and set on the database connection consists of the thread ID, user name, user location, and application name.

Important: User name and user location can be implicitly collected and set only on the database connection if you enable Java 2 security.

(zos) thread ID

An eight-character hexadecimal value identifying Java thread that controls the processing of the application request within WebSphere Application Server. This ID is displayed in the trace header.

user name

The name of the user that initiates the application request. This option is collected and passed to the backend database (when supported). Information here is collected by calling the WSSecurityHelper.getFirstCaller method.

user location

The name of the location of the user, in the form of cell:node:server. This option is collected and passed to the backend database (when appropriate). Information here is collected by calling the WSSecurityHelper.getFirstServer method.

application name

The name of the application running. Output of the getApplication method from the Java EE Name object. This value is collected regardless of the Global Security setting.

WAS.clientinfopluslogging trace

When debugging database problems, such as deadlocks, there is a set of information that may help with the debugging effort. This information is typically obtained by enabling a WebSphere Relational Resource Adapter (RRA) trace, and an EJB container trace. However, there are some cases where timing is an issue when reproducing a given problem. Having too much tracing information can alter the behavior of the application, such as change the timing, and the problem might no longer occur.

Because of this situation, a new trace group is provided where only a minimum set of information is collected. This trace group is WAS.clientinfopluslogging. This function sets the client information implicitly on the connection, just like the WAS.clientinfo trace, and, logs and traces important application activities. Those activities are:

• SQL strings that are run (such as, select userId from tabl1 where id=? for update).

• Start, commit, and rollback of transactions.

• EJB calls (such as, Create, Remove, findByPrimaryKey).

Related tasks

Enable client information tracing with the administrative console