WAS v8.5 > End-to-end paths > Data access resources

Passing client information to a database

Using a WebSphere Application Server API or trace function, we can pass unique client information about every connection that originates from the same data source. Some databases, such as DB2 , support a data source custom property that triggers the database servers to extract client information from WAS connections. (Consult the database documentation to see whether the product supports this capability and which property the product requires.) Be aware, however, these properties introduces limited functionality in WAS. Consequently, an application server connection manager incurs the following risky behaviors, which can result in the transfer of wrong client information to the database.

• The connection manager cannot change client information about the data source, or the connections obtained from that data source, dynamically.
• The connection manager must set the same client information about all connections that are obtained from that data source. For example, if you set ApplicationName as part of the data source clientInformation property, all connections from that data source have the same application name.

Application Server offers two methods of passing client information that provide the necessary connection management flexibility. Either method is used to set client information about some connections and not others, as well as set different client information about different database connections from the same data source.

• Use the IBM proprietary setClientInformation(Properties) API. The API is defined on the WSConnection class, which is part of the plugins_root/com.ibm.ws.runtime.jar file.
  1. Cast the connection objects in the applications to com.ibm.websphere.rsadapter.WSConnection before calling the API.

  2. Optionally, set a properties object for adding new client information about a connection if and when new information is introduced by the backend database:
     public void setClientInformation (Properties props)throws SQLException;

• We can also activate the function implicitly (that is, within WAS) using the WAS.clientinfo trace string. Enable this trace dynamically, from the dmgr console, just as you activate any other trace. For more information about passing client information implicitly, see the topic Implicitly set client information.

Results

Example: Setting client information with the setClientInformation(Properties) API.

We can set WAS client information on connections to pass that information to the database with this API.

The following example code calls setClientInformation(Properties) on the com.ibm.websphere.rsadapter.WSConnection object.

import com.ibm.websphere.rsadapter.WSConnection;
.....
try {
   InitialContext ctx = new InitialContext();
   //Perform a naming service lookup to get the DataSource object.
   DataSource ds = (javax.sql.DataSource)ctx.lookup("java:comp/jdbc/myDS");
  }catch (Exception e) {System.out.println("got an exception during lookup: " + e);}

  WSConnection conn = (WSConnection) ds.getConnection();
  Properties props = new properties();
  props.setProperty(WSConnection.CLIENT_ID, "user123");
  props.setProperty(WSConnection.CLIENT_LOCATION, "127.0.0.1");
  props.setProperty(WSConnection.CLIENT_ACCOUNTING_INFO, "accounting");
  props.setProperty(WSConnection.CLIENT_APPLICATION_NAME, "appname");
  props.setProperty(WSConnection.CLIENT_OTHER_INFO, "cool stuff");
  conn.setClientInformation(props);
  conn.close()

Parameters

props contains the client information to be passed. Possible values are:

• WSConnection.CLIENT_ACCOUNTING_INFO
• WSConnection.CLIENT_LOCATION
• WSConnection.CLIENT_ID
• WSConnection.CLIENT_APPLICATION_NAME
• WSConnection.CLIENT_OTHER_INFO
• WSConnection.OTHER_CLIENT_TYPE

Refer to the WSConnection documentation for more details on which client information is passed to the backend database. To reset the client information, call the method with a null parameter.

Exceptions

This API creates an SQL exception if the database issues an exception when setting the data.

Subtopics

• Implicitly set client information
  If you track client information in the database, we can choose one of two ways to pass WAS client data on database connections.
• Enable client information tracing with the dmgr console
  Use either of the methods outlined in this task to enable the passing and tracing of client information about a database connection.

+

Search Tips   |   Advanced Search