Guide to CORBA University Sample Applications

The Production Sample Application

This topic includes the following sections:

How the Production Sample Application Works

The Production sample application provides the same end-user functionality as the Wrapper sample application. The Production sample application demonstrates how to use CORBA features of the BEA Tuxedo software to scale a CORBA application. The Production sample application does the following:

The following sections describe how the Production sample application uses replicated server applications, replicated server groups, object state management, and factory-based routing to scale the Production sample application.

Replicating Server Applications

When you replicate server applications:

In the Production sample application, the server applications are replicated in the following manner:

Figure 7-1 shows the replicated ORA_GRP and APP_GRP server groups.

In Figure 7-1, note the following:

Replicating Server Groups

Server groups are a feature of the BEA Tuxedo software that allow you to add server machines to an existing CORBA application. When you replicate a server group, you can do the following:

The way in which server groups are configured and replicated is specified in the UBBCONFIG file.

Figure 7-2 shows the server groups in the Production sample application replicated on a second server machine. The replicated server groups are defined as ORA_GRP2 and APP_GRP2 in the UBBCONFIG file for the Production sample application.

In Figure 7-2, the only difference between the content of the server groups on Production Machine 1 and Production Machine 2 is the database. The University database is partitioned into two databases. The database on Production Machine 1 contains student and account information for students with IDs between 100001 and 100005. The database on Production Machine 2 contains student and account information for students with IDs between 100006 and 100010.

Using a Stateless Object Model

To achieve scalability gains, the Registrar and Teller objects are configured in the Production sample application to have the method activation policy. The method activation policy results in the following behavior changes:

In the Basic through the Production sample applications, the Registrar object had an activation policy of process. All requests from client applications on the Registrar object went to the same object instance in the memory of the server machine. This design is adequate for a small-scale deployment. However, as client application demands increase, requests from client applications on the Registrar object eventually become queued, and response time drops.

However, when the Registrar and Teller objects have an activation policy of method and the server applications that manage these objects are replicated, the Registrar and Teller objects can process multiple requests from client applications in parallel. The only constraint is the number of server application processes that are available to instantiate the Registrar and Teller objects.

For the CORBA application to instantiate copies of the Registrar and Teller objects in each of the replicated server application processes, each copy of the Registrar and Teller objects have an unique object ID (OID). The factories that create these objects are responsible for assigning them unique OIDs. For information about generating unique object IDs, see Creating CORBA Server Applications.

Using Factory-based Routing

Factory-based routing is a CORBA feature that allows you to send a request from a client application to a specific server group. Using factory-based routing, you can spread the processing load for a CORBA application across multiple server machines. The Production sample application uses factory-based routing in the following way:

For information about setting up factory-based routing, see Creating CORBA Server Applications.

The Development Process for the Production Sample Application

This section describes the development process required when scaling a CORBA application. These steps are in addition to the development process outlined in The Basic Sample Application.

OMG IDL

During the development process, to support factory-based routing, you would make modifications to the Object Management Group (OMG) Interface Definition Language (IDL) definitions for the following operations:

For information about implementing factory-based routing, see Creating CORBA Server Applications.

The Client Application

During the development process, you would specify a STU_ID value when creating a Registrar object. The STU_ID value defines to which server group the request from the client application is routed.

In the Production sample application, the University server application creates the Teller object in the same way a client application would. Therefore, an ACT_NUM value needs to be specified when creating a Teller object.

The Server Application

During the development process, you need to modify the invocation to the TP::create_object_reference() operation for the RegistrarFactory and TellerFactory objects to include an NVlist that specifies routing criteria. The criteria parameter of the TP::create_object_reference()operation specifies a list of named values to be used for factory-based routing, as follows:

The value of the criteria parameter must match exactly the routing criteria name, field, and field type specified in the ROUTING section of the UBBCONFIG file.

For information about implementing factory-based routing in a factory, see Creating CORBA Server Applications.

The UBBCONFIG File

The UBBCONFIG file is the key to achieving scalability in a CORBA application. This section describes how the UBBCONFIG file for the Production sample application is modified to:

Replicating Server Application Processes and Server Groups

During the development process, modify the UBBCONFIG file in the following way to configure replicated server application processes and server groups:

The MIN and MAX parameters determine the degree to which a given server application can process requests in parallel on a given object. During run time, the system administrator can examine resource bottlenecks and start additional server processes, if necessary. In this sense, the application is scaled by the system administrator.

The following example shows lines from the GROUPS and SERVERS sections of the UBBCONFIG file for the Production sample application.

*GROUPS
    APP_GRP1
        LMID      = SITE1
        GRPNO     = 2
        TMSNAME   = TMS
    APP_GRP2
        LMID      = SITE1
        GRPNO     = 3
        TMSNAME   = TMS
    ORA_GRP1
        LMID      = SITE1
        GRPNO     = 4
        OPENINFO  = "ORACLE_XA:Oracle_XA+Acc=P/scott/tiger+SesTm=100+LogDir
                     =.+MaxCur=5"
        CLOSEINFO = ""
        TMSNAME   = "TMS_ORA"
    ORA_GRP2
        LMID      = SITE1
        GRPNO     = 5
        OPENINFO  = "ORACLE_XA:Oracle_XA+Acc=P/scott/tiger+SesTm=100+LogDir
                    =.+MaxCur=5"
        CLOSEINFO = ""
        TMSNAME   = "TMS_ORA"
		

*SERVERS
    # By default, activate 2 instances of each server
    # and allow the administrator to activate up to 5
    # instances of each server
    DEFAULT:
        MIN     = 2
        MAX     = 5
    tellp_server
        SRVGRP  = ORA_GRP1
        SRVID   = 10
        RESTART = N
    tellp_server
        SRVGRP  = ORA_GRP2
        SRVID   = 10
        RESTART = N
    billp_server
        SRVGRP  = APP_GRP1
        SRVID   = 10
        RESTART = N
    billp_server
        SRVGRP  = APP_GRP2
        SRVID   = 10
        RESTART = N
    univp_server
        SRVGRP  = ORA_GRP1
        SRVID   = 20
        RESTART = N
    univp_server
        SRVGRP  = ORA_GRP2
        SRVID   = 20
        RESTART = N

Implementing Factory-based Routing

For each interface for which you want to enable factory-based routing, you need to define the following information in the UBBCONFIG file:

During the development process, make the following changes to the UBBCONFIG file:

The ICF File

During the development process, you need to change the activation policy of the Registrar, RegistrarFactory, Teller, and TellerFactory objects from process to method. For information about defining activation and transaction policies for CORBA objects, see Creating CORBA Server Applications.

Building the Production Sample Application

To build the Production sample application, complete the following steps:

The following sections describe these steps.

Copying the Files for the Production Sample Application into a Work Directory

The files for the Production sample application are located in the following directories:

Windows

drive:\TUXDIR\samples\corba\university\production

UNIX

/usr/TUXDIR/samples/corba/university/production

In addition, you need to copy the utils directory into your work directory. The utils directory contains files that set up logging, tracing, and access to the University database.

You will use the files in Table 7-1 to create the Production sample application.

Changing the Protection on the Files for the Production Sample Application

During the installation of the BEA Tuxedo software, the sample application files are marked read-only. Before you can edit the files or build the files in the Production sample application, you need to change the protection of the files you copied into your work directory, as follows:

Windows

prompt>attrib -r drive:\workdirectory\*.*

UNIX

prompt>chmod u+rw /workdirectory/*.*

Setting the Environment Variables

Use the following command to set the environment variables used to build the client and server applications in the Production sample application:

Windows

prompt>setenvp

UNIX

prompt>/bin/ksh

prompt>. ./setenvp.sh

Initializing the University Database

Use the following command to initialize the University database used with the Production sample application:

Windows

prompt>nmake -f makefilep.nt initdb

UNIX

prompt>make -f makefilep.mk initdb

Loading the UBBCONFIG File

Use the following command to load the UBBCONFIG file:

Windows

prompt>tmloadcf -y ubb_p.nt

UNIX

prompt>tmloadcf -y ubb_p.mk

The build process for the UBBCONFIG file prompts you for an application password. This password will be used to log on to the client applications. Enter the password and press Enter. You are then prompted to verify the password by entering it again.

Creating a Transaction Log

The transaction log records the transaction activities in a CORBA application. During the development process you need to define the location of the transaction log (specified by the TLOGDEVICE parameter) in the UBBCONFIG file. For the Production sample application, the transaction log is placed in your work directory.

You need to complete the following steps to open the transaction log for the Production sample application:

Compiling the Production Sample Application

During the development process, you would use the buildobjclient and buildobjserver commands to build the client and server applications. However, for the Production sample application, this step has been done for you. The directory for the Production sample application contains a makefile that builds the client and server sample applications.

Use the following commands to build the CORBA C++ client and server application in the Production sample application:

Windows

prompt>nmake -f makefilep.nt

UNIX

Running the Production Sample Application

To run the Production sample application, complete the following steps:

The following sections describe these steps in detail.

Starting the Server Application

Start the system and sample application server applications in the Production sample application by entering the following command:

prompt>tmboot -y

This command starts the following server processes:

Before using another sample application, enter the following command to stop the system and sample application server processes:

prompt>tmshutdown

Starting the CORBA C++ Client Application

Start the CORBA C++ client application in the Production sample application by completing the following steps:

How the Production Sample Application Can Be Scaled Further

The Production sample application can be scaled even more by: