Configuring Multi Data Source in Weblogic (Load-Balancing between Data Sources)

We can Create a Multi data Source in Weblogic which can perform Load balancing/ Fail-over among multiple generic Data sources. The Applications deployed on Weblogic will point to this Multi data Source and This Multidata source will do the load balancing/ fail-over internally.

Below are the steps to create a Multi data source:

• Login to the weblogic console and click services. Click on Data Sources and create a new generic data source.

• Provide all the connection details and test the connection with Database.

• After this create another generic Data source. MultiData Source will do a load balancing between these 2 data sources. 
• After both the data sources are created. Click on Services--> Data Sources. Create a new Multi Data Source.

• Provide the name of the Multi data source, JNDI name of the Data Source and select either load balancing or Fail-Over from Algorithm type. 

• Select the server where Multidata source will be deployed (Server where application would be running).

• Select the type of driver.

• Add all the generic data sources to Multi data source. click Finish.
• Now Multidata source is created and can be used by applications to connect.
• Below is a sample java code through which we can connect to Multi data source which internally will connect to any of generic data source.

Context ctx = null;

      Hashtable ht = new Hashtable();

      ht.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");

      ht.put(Context.PROVIDER_URL,"t3://<Weblogic_host>:<port>");

       Connection conn = null;

        ctx = new InitialContext(ht);

        javax.sql.DataSource ds 

          = (javax.sql.DataSource) ctx.lookup ("JDBC Multi Data Source-0"); //Name of Multi data source

        conn = ds.getConnection();

return conn;