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Software-Entwicklung Java

Accessing JDBC Data Source metrics from an application on a Weblogic Server

I recently felt the need for accessing the metrics / statistics of a JDBC Data Source from within an application that is deployed on a Oracle Weblogic Server. I did not succeed right away, so I document it here.

Basically we just need some calls to JMX. Using the Weblogic RuntimeServiceMBean we navigate from ServerRuntime and JDBCServiceRuntime to JDBCDataSourceRuntimeMBeans. From there we get ObjectNames for each JDBC Data Source that we can access from our application. Using these object names we can retreive the metrics.

First we get the MBeanServer via JNDI:

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java

  1. MBeanServer getMBeanServer() throws NamingException {
  2.   InitialContext ctx = new InitialContext();
  3.   MBeanServer server = (MBeanServer) ctx.lookup("java:comp/env/jmx/runtime");
  4.   return server;
  5. }

Then we navigate as described before:

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java

  1. ObjectName[] getJdbcDataSourceRuntimeMBeans(MBeanServer server)
  2.       throws MalformedObjectNameException, AttributeNotFoundException, MBeanException,
  3.       InstanceNotFoundException, ReflectionException {
  4.     ObjectName service = new ObjectName(
  5. "com.bea:Name=RuntimeService,Type=weblogic.management.mbeanservers.runtime.RuntimeServiceMBean");
  6.     ObjectName serverRT = (ObjectName) server.getAttribute(service, "ServerRuntime");
  7.     ObjectName jdbcRT = (ObjectName) server.getAttribute(serverRT, "JDBCServiceRuntime");
  8.     ObjectName[] dsRTs = (ObjectName[]) server.getAttribute(jdbcRT, "JDBCDataSourceRuntimeMBeans");
  9.     return dsRTs;
  10.   }

To get the current number of active connections and the current capacity of the connection pool, we access the attributes ActiveConnectionsCurrentCount and CurrCapacity:

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java

  1. MBeanServer server = getMBeanServer();
  2.       ObjectName[] dsRTs = getJdbcDataSourceRuntimeMBeans(server);
  3.       for (ObjectName dsRT : dsRTs) {
  4.         String name = (String) server.getAttribute(dsRT, "Name");
  5.         Integer activeConnectionsCurrentCount =
  6.             (Integer) server.getAttribute(dsRT, "ActiveConnectionsCurrentCount");
  7.         Integer currCapacity =
  8.             (Integer) server.getAttribute(dsRT, "CurrCapacity");
  9.     // do something with these metrics
  10.       }

There are a bunch of metrics. Here is a list. You can enumerate them using MBeanAttrbuteInfo:

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java

  1. /**
  2.    * Returns MBean-Attribute Infos such as Name, Type and Description
  3.    */
  4.   public MBeanAttributeInfo[] getMetricsAttributeInfos() {
  5.     try {
  6.       MBeanServer server = getMBeanServer();
  7.       ObjectName[] dsRTs = getJdbcDataSourceRuntimeMBeans(server);
  8.       if (dsRTs.length>0) {
  9.         return server.getMBeanInfo(dsRTs[0]).getAttributes();
  10.       }
  11.     } catch (Exception e) {
  12.       // your favourite error logging mechanism here...
  13.     }
  14.     return new MBeanAttributeInfo[]{};
  15.    
  16.   }

every MBeanAttributeInfo contains name, type and description of the attribute.

Note: I am using Weblogic Server 11g here. I have not tried this on WLS 12c.

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