Thursday Nov 19, 2015

WLS Replay Statistics

Starting in the Oracle thin driver, the replay driver has statistics related to replay. This is useful to understand how many connections are being replayed. It should be completely transparent to the application so you won’t know if connection replays are occurring unless you check.

The statistics are available on a per connection basis or on a datasource basis. However, connections on a WLS datasource don’t share a driver-level datasource object so the latter isn’t useful in WLS. WLS 12.2.1 provides another mechanism to get the statistics at the datasource level.

The following code sample shows how to print out the available statistics for an individual connection using the oracle.jdbc.replay.ReplayableConnection interface, which exposes the method to get a oracle.jdbc.replay.ReplayStatistics object. See for a description of the statistics values.

if (conn instanceof ReplayableConnection) {
  ReplayableConnection rc = ((ReplayableConnection)conn);
  ReplayStatistics rs = rc.getReplayStatistics(
  System.out.println("Individual Statistics");

Besides a getReplayStatistics() method, there is also a clearReplayStatistics() method.

To provide for a consolidated view of all of the connections associated with a WLS datasource, the information is available via a new operation on the associated runtime MBean. You need to look-up the WLS MBean server, get the JDBC service, then search for the datasource name in the list of JDBC datasource runtime MBeans, and get the JDBCReplayStatisticsRuntimeMBean. This value will be null if the datasource is not using a replay driver, if the driver is earlier than, or if it’s not a Generic or AGL datasource. To use the replay information, you need to first call the refreshStatistics() operation that sets the MBean values, aggregating the values for all connections on the datasource. Then you can call the operations on the MBean to get the statistics values, as in the following sample code. Note that there is also a clearStatistics() operation to clear the statistics on all connections on the datasource. The following code shows an example of how to print the aggregated statistics from the data source.

public void printReplayStats(String dsName) throws Exception {
  MBeanServer server = getMBeanServer();
  ObjectName[] dsRTs = getJdbcDataSourceRuntimeMBeans(server);
  for (ObjectName dsRT : dsRTs) {
    String name = (String)server.getAttribute(dsRT, "Name");
    if (name.equals(dsName)) {
      ObjectName mb =(ObjectName)server.getAttribute(dsRT,  
      server.invoke(mb,"refreshStatistics", null, null);
      MBeanAttributeInfo[] attributes = server.getMBeanInfo(mb).getAttributes();
      for (int i = 0; i <attributes.length; i++) {
        if(attributes[i].getType().equals("java.lang.Long")) {
            (Long)server.getAttribute(mb, attributes[i].getName()));

MBeanServer getMBeanServer() throws Exception {
  InitialContext ctx = new InitialContext();
  MBeanServer server = (MBeanServer)ctx.lookup("java:comp/env/jmx/runtime");
  return server;
ObjectName[] getJdbcDataSourceRuntimeMBeans(MBeanServer server) 
  throws Exception {
  ObjectName service = new ObjectName( "com.bea:Name=RuntimeService,Type=\");
  ObjectName serverRT = (ObjectName)server.getAttribute(service,  "ServerRuntime");
  ObjectName jdbcRT = (ObjectName)server.getAttribute(serverRT,  "JDBCServiceRuntime");
  ObjectName[] dsRTs = (ObjectName[])server.getAttribute(jdbcRT,
  return dsRTs;

Now run an application that gets a connection, does some work, kills the session, replays, then gets a second connection and does the same thing. Each connection successfully replays once. That means that the individual statistics show a single replay and the aggregated statistics will show two replays. Here is what the output might look like.

Individual Statistics


Looking carefully at the numbers, you can see that the individual count was done before the connections were closed (TotalCompletedRequests=0) and the roll-up was done after both connections were closed. 

You can also use WLST to get the statistics values for the datasource. The statistics are not visible in the administration console or FMWC in WLS 12.2.1.

Thursday Nov 12, 2015

WLS UCP Datasource

WebLogic Server (WLS) 12.2.1 introduces a new datasource type that uses the Oracle Universal Connection Pool (UCP) as an alternative connection pool.  The UCP datasource allows for configuration, deployment, and monitoring of the UCP connection pool as part of the WLS domain.  It is certified with the Oracle Thin driver (simple, XA, and replay drivers). 

The product documentation is at .  The goal of this article  is not to reproduce that information but to summarize the feature and provide some additional information and screen shots for configuring the datasource.

A UCP data source is defined using a jdbc-data-source descriptor as a system resource.  With respect to multi-tenancy, these system resources can be defined at the domain, partition, resource group template, or resource group level. 

The configuration  for a UCP data source is pretty simple with the standard datasource parameters.  You can  name it, give it a URL, user, password and JNDI name.  Most of the detailed configuration and tuning comes in the form of UCP connection properties.  The administrator can configure values for any setters supported by oracle.ucp.jdbc.PoolDataSourceImpl except LogWriter  (see oracle.ucp.PoolDaaSourceImpl) by just removing the "set" from the attribute name (the names are case insensitive).  For example,


Table 8-2 in the documentation lists all of the UCP attributes that are currently supported, based on the UCP jar that ships with WLS 12.2.1.

There is some built-in validation of the (common sense) combinations of driver and connection factory:


Factory (ConnectionFactoryClassName)

oracle.ucp.jdbc.PoolDataSourceImpl (default)






To simplify the configuration, if the "driver-name" is not specified, it will default to oracle.ucp.jdbc.PoolDataSourceImpl  and the ConnectionFactoryClassName connection property defaults to the corresponding entry from the above table.

Example 8.1 in the product documentation gives a complete example of creating a UCP data source using WLST.   WLST usage is very common for application configuration these days.

Monitoring is available via the  This MBean extends JDBCDataSourceRuntimeMBean so that it can be returned with the list of other JDBC MBeans from the JDBC service for tools like the administration console or your WLST script.  For a UCP data source, the state and the following attributes are set: CurrCapacity, ActiveConnectionsCurrentCount, NumAvailable, ReserveRequestCount, ActiveConnectionsAverageCount, CurrCapacityHighCount, ConnectionsTotalCount, NumUnavailable, and WaitingForConnectionSuccessTotal.

The administration console and FMWC make it easy to create, update, and monitor UCP datasources.

The following images are from the administration console. For the creation path, there is a drop-down that lists the data source types; UCP is one of the choices.  The resulting data source descriptor datasource-type set to "UCP".

The first step is to specify the JDBC Data Source Properties that determine the identity of the data source. They include the datasource names, the scope (Global or Multi Tenant Partition, Resource Group, or Resource Group Template) and the JNDI names.

The next page handles the user name and password, URL, and additional connection properties. Additional connection properties are used to configure the UCP connection pool. There are two ways to provide the connection properties for a UCP data source in the console. On the Connection Properties page, all of the available connection properties for the UCP driver are displayed so that you only need to enter the property value.  On the next page for Test Database Connection, you can enter a propertyName=value directly into the Properties text box.  Any values entered on the previous Connection Properties page will already appear in the text box.  This page can be used to test the specified values including the connection properties.

The Test Database Connection page allows you to enter free-form values for properties and test a database connection before the data source configuration is finalized. If necessary, you can provide additional configuration information using the Properties, System Properties, and Encrypted Properties attributes.

The final step is to target the data source. You can select one or more targets to which to deploy your new UCP data source. If you don't select a target, the data source will be created but not deployed. You will need to deploy the data source at a later time before you can get a connection in the application.

For editing the data source, minimal tabs and attributes are exposed to configure, target, and monitor this data source type.

The capabilities in FMWC are similar to the administrative console but with a different look and feel.

If you select JDBC Data Sources from the WebLogic Domain drop-down, you will see a list of existing data sources with their associated data source type, scope, and if applicable RG, RGT and Partition.

Selecting an existing DS name brings up a page to edit the DS.

Selecting a resource group name (if it exists) brings up a page to edit the RG.

Selecting a partition name of an existing data source brings up a page to edit the Partition attributes.

Selecting Create displays a data source type drop-down where you can select UCP Data Source.

The first page of the UCP creation requires the data source name, scope, JNDI names(s), and selecting a driver class name.