Oracle RAC (Real Application Cluster)

Important Links:

• Implicit Connection Cache

          http://download-west.oracle.com/docs/cd/B19306_01/java.102/b14355/concache.htm

• FCF 

          http://download-west.oracle.com/docs/cd/B19306_01/java.102/b14355/fstconfo.htm#CIHJBFFC

Property fcf-cache file:

# properties required for test

username=scott

password=tiger

InitialLimit=10

MinLimit=10

MaxLimit=20

onsconfig=nodes=aulnx4-vip.au.oracle.com:6200,aulnx3-vip.au.oracle.com:6200

url=jdbc:oracle:thin:@(DESCRIPTION= \

    (LOAD_BALANCE=yes) \

       (ADDRESS=(PROTOCOL=TCP)(HOST=aulnx4-vip.au.oracle.com)(PORT=1521)) \

       (ADDRESS=(PROTOCOL=TCP)(HOST=aulnx3-vip.au.oracle.com)(PORT=1521)) \

       (CONNECT_DATA=(service_name=sales2)))

Java API to support Oracle RAC

public class FCFConnectionCacheExample

{

  private OracleDataSource ods = null;

  private OracleConnectionCacheManager occm = null;

  private Properties cacheProperties = null;

  

  public FCFConnectionCacheExample() throws SQLException

  {

    // create a cache manager

    occm = OracleConnectionCacheManager.getConnectionCacheManagerInstance();

    Properties props = loadProperties("fcfcache");

    

    cacheProperties = new java.util.Properties();

    cacheProperties.setProperty("InitialLimit", (String)props.get("InitialLimit"));

    cacheProperties.setProperty("MinLimit", (String)props.get("MinLimit"));

    cacheProperties.setProperty("MaxLimit", (String)props.get("MaxLimit"));

    

    ods = new OracleDataSource();

    ods.setUser((String)props.get("username"));

    ods.setPassword((String)props.get("password"));

    ods.setConnectionCachingEnabled(true);

    ods.setFastConnectionFailoverEnabled(true);

    ods.setConnectionCacheName("MyCache");

    ods.setONSConfiguration((String)props.get("onsconfig"));

    ods.setURL((String)props.get("url"));

    occm.createCache("MyCache", ods, cacheProperties);

  }

  private Properties loadProperties (String file)

  {

    Properties prop = new Properties();

    ResourceBundle bundle = ResourceBundle.getBundle(file);

    Enumeration enumlist = bundle.getKeys();

    String key = null;

    while (enumlist.hasMoreElements()) 

    {

       key = (String) enumlist.nextElement();

       prop.put(key, bundle.getObject(key));

    }

    

    return prop;

  }

  

  public void run() throws Exception

  {

    Connection conn = null;

    Statement stmt = null;

    ResultSet rset = null;

    String sQuery = 

        "select sys_context('userenv', 'instance_name'), " + 

               "sys_context('userenv', 'server_host'), " + 

               "sys_context('userenv', 'service_name') " + 

        "from dual";

        

    try

    {

      conn = null;

      conn = ods.getConnection();

      stmt = conn.createStatement();

      rset = stmt.executeQuery(sQuery);

      rset.next();

      System.out.println("-----------");

      System.out.println("Instance -> " + rset.getString(1));

      System.out.println("Host -> " + rset.getString(2));

      System.out.println("Service -> "  + rset.getString(3));

      System.out.println("NumberOfAvailableConnections: " +

                          occm.getNumberOfAvailableConnections("MyCache"));

      System.out.println("NumberOfActiveConnections: " +

                          occm.getNumberOfActiveConnections("MyCache"));

      System.out.println("-----------");

    }

    catch (SQLException sqle)

    {

      while (sqle != null) 

      {

          System.out.println("SQL State: " + sqle.getSQLState());

          System.out.println("Vendor Specific code: " +

                             sqle.getErrorCode());

          Throwable te = sqle.getCause();

          while (te != null) {

              System.out.print("Throwable: " + te);

              te = te.getCause();

          }

          sqle.printStackTrace();

          sqle = sqle.getNextException();

      }

    }

    finally

    {

      try

      {

        rset.close();

        stmt.close();

        conn.close();      

      }

      catch (SQLException sqle2)

      {

         System.out.println("Error during close");

      }

    }

  }  

  

  public static void main(String[] args)

  {  

    System.out.println(">> PROGRAM using JDBC thin driver no oracle client required");

    System.out.println(">> ojdbc14.jar and ons.jar must be in the CLASSPATH");

    System.out.println(">> Press CNTRL C to exit running program\n");

    try

    {

      FCFConnectionCacheExample test = new FCFConnectionCacheExample();

      while (true)

      {

        test.run();

        Thread.currentThread().sleep(10000);

      }

    }

    catch (InterruptedException e)

    {

      System.out.println("PROGRAM Ended by user");

    }

    catch (Exception ex)

    {

      System.out.println("Error Occurred in MAIN");

      ex.printStackTrace();

    }

  }

}