Several settings are available for controlling internal ORB processing. You can use these settings to improve application performance in the case of applications that contain enterprise beans. You can make changes to these settings for the default server or any appserver that is configured in the administrative domain.
- Request timeout
- Number of seconds to wait before timing out on a request message.
If you use command-line scripting, the full name of this system property is com.ibm.CORBA.RequestTimeout.
| Data type
| int
|
| Units
| Seconds |
| Default
| 180
|
| Range
| 0 - largest integer recognized by Java
|
- Request retries count
- Number of times that the ORB attempts to send a request if a server fails. Retrying sometimes enables recovery from transient network failures. This field is ignored on the z/OS platform.
If you use command-line scripting, the full name of this system property is com.ibm.CORBA.requestRetriesCount.
| Data type
| int
|
| Default
| 1
|
| Range
| 1 to 10
|
- Request retries delay
- Number of milliseconds between request retries. This field is ignored on the z/OS platform.
If you use command-line scripting, the full name of this system property is com.ibm.CORBA.requestRetriesDelay.
| Data type
| int
|
| Units
| Milliseconds
|
| Default
| 0
|
| Range
| 0 to 60,000
|
- Connection cache maximum
-
Maximum number of entries that can occupy the ORB connection cache before the ORB starts to remove inactive connections from the cache. This field is ignored on the z/OS platform.
It is possible that the number of active connections in the cache will temporarily exceed this threshold value. If necessary, the ORB will continue to add connections as long as resources are available.
For use in command-line scripting, the full name of this system property is com.ibm.CORBA.MaxOpenConnections.
| Data type
| Integer
|
| Units
| Connections
|
| Default
| 240
|
| Range
| 10 - largest integer recognized by Java
|
- Connection cache minimum
-
Minimum number of entries in the ORB connection cache.
This field is ignored on the z/OS platform.
The ORB will not remove inactive connections when the number of entries is below this value.
For use in command-line scripting, the full name of this system property is com.ibm.CORBA.MinOpenConnections.
| Data type
| Integer
|
| Units
| Connections
|
| Default
| 100
|
| Range
| Any integer that is at least 5 less than the value specified for the Connection cache maximum property.
|
- ORB tracing
-
Enables the tracing of ORB General Inter-ORB Protocol (GIOP) messages.
This setting affects two system properties:
- com.ibm.CORBA.Debug
- com.ibm.CORBA.CommTrace
If you set these properties through command-line scripting, set both properties to true to enable the tracing of GIOP messages.
| Data type
| Boolean
|
| Default
| Not enabled (false)
|
- Locate request timeout
- Number of seconds to wait before timing out on a
LocateRequest message. This field is ignored on the z/OS platform.
If you use command-line scripting, the full name of this system property is com.ibm.CORBA.LocateRequestTimeout.
| Data type
| int
|
| Units
| Seconds
|
| Default
| 180
|
| Range
| 0 to 300
|
- Force tunneling
-
Controls how the client ORB attempts to use HTTP tunneling. This field is ignored on the z/OS platform.
If you use command-line scripting, the full name of this system property is com.ibm.CORBA.ForceTunnel.
| Data type
| String
|
| Default
| NEVER
|
| Range
| Valid values are ALWAYS, NEVER, or WHENREQUIRED.
|
Considering the following information when choosing the valid value:
- ALWAYS
-
Use HTTP tunneling immediately, without trying TCP connections first.
- NEVER
-
Disable HTTP tunneling. If a TCP connection fails, a CORBA system exception (COMM_FAILURE) occurs.
- WHENREQUIRED
-
Use HTTP tunneling if TCP connections fail.
- Tunnel agent URL
-
Specify the Web address of the servlet to use in support of HTTP tunneling. This field is ignored on the z/OS platform.
This Web address must be a proper format:
http://w3.mycorp.com:81/servlet/com.ibm.CORBA.services.IIOPTunnelServlet
For applets:
http://applethost:port/servlet/com.ibm.CORBA.services.IIOPTunnelServlet
This field is required if HTTP tunneling is set. If you use command-line scripting, the full name of this system property is...
com.ibm.CORBA.TunnelAgentURL
- Pass by reference
-
Specify how the ORB passes parameters.
If enabled, the ORB passes parameters by reference instead of by value, to avoid making an object copy. If you do not enable the pass by reference option, a copy of the parameter passes rather than the parameter object itself. This can be expensive because the ORB must first make a copy of each parameter object.
You can use this option only when the EJB client and the EJB are on the same classloader. This requirement means that the EJB client and the EJB must be deployed in the same EAR file.
If the EJB client and server are installed in the same WAS instance, and the client and server use remote interfaces, enabling the pass by reference option can improve performance up to 50%. The pass by reference option helps performance only where non-primitive object types are passed as parameters. Therefore, int and floats are always copied, regardless of the call model.
Enable this property with caution because unexpected behavior can occur. If an object reference is modified by the callee, the caller's object is modified as well, since they are the same object.
If you use command-line scripting, the full name of this system property is com.ibm.CORBA.iiop.noLocalCopies.
| Data type
| Boolean
|
| Default
| Not enabled (false)
|
The use of this option for enterprise beans with remote interfaces violates
EJB Specification, V2.0 (see section 5.4). Object references passed to EJB methods or to EJB home methods are not copied and can be subject to corruption.
Consider the following example:
Iterator iterator = collection.iterator();
MyPrimaryKey pk = new MyPrimaryKey();
while (iterator.hasNext())
{
pk.id = (String) iterator.next();
MyEJB myEJB = myEJBHome.findByPrimaryKey(pk);
}
In this example, a reference to the same MyPrimaryKey object passes into WAS with a different ID value each time. Running this code with pass by reference enabled causes a problem within the appserver because multiple enterprise beans are referencing the same MyPrimaryKey object. To avoid this problem, set the system property...
com.ibm.websphere.ejbcontainer.allowPrimaryKeyMutation
... system property to true when the pass by reference option is enabled. Setting the pass by reference option to true causes the EJB container to make a local copy of the PrimaryKey object. As a result, however, a small portion of the performance advantage of setting the pass by reference option is lost.
As a general rule, any application code that passes an object reference as a parameter to an enterprise bean method or to an EJB home method must be scrutinized to determine if passing that object reference results in loss of data integrity or in other problems.
After examining your code, you can enable the pass by reference option by setting the system property...
com.ibm.CORBA.iiop.noLocalCopies
...to true.
You can also enable the pass by reference option in the console. Click...
Servers | Application servers | server_name | Container services | ORB Service | Pass by reference