Implicitly set client information
If you track client information in your database, you can choose one of two ways to pass WebSphere® Application Server client data on database connections.
- You want to keep your application free of proprietary APIs, or
- Your application uses container-managed persistence (CMP), in which case you 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. You 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-existenceWhen 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:
Where 000325 is the thread ID and WSRdbManagedConnectionImpl@1234 is the WebSphere connection instance.000325_WSRdbManagedConnectionImpl@1234_myAccountingInfo:
- 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. You can turn on this mechanism dynamically, without stopping and starting your application server, or statically by setting the WebSphere Application Server 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.
The information implicitly collected and set on the
database connection consists of the thread ID, user name, user location,
and application name.
thread ID
An eight-character hexadecimal value that identifies the 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. This value is the 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 Enterprise JavaBeans (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.
- 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).