WebSphere Message Brokers
File: ac00900_
Writer: Karen Cameron

Task topic

This build: July 31, 2007 21:16:58

Configuring global coordination with DB2 using a 32-bit queue manager

If you want to globally coordinate message flow transactions with updates in DB2 databases, configure the broker environment. This topic describes how to configure the broker environment when the broker uses a 32-bit queue manager.

Before you start:

All WebSphere MQ Version 6 queue managers on 32-bit platforms are 32-bit. 32-bit queue managers can coordinate transactions only in 32-bit mode and can coordinate only message flows that are deployed to 32-bit execution groups.

To configure your broker environment for global coordination using a 32-bit queue manager as the transaction manager:

  1. Decide whether the broker will connect to databases using TCP/IP or using shared memory.

    For more information about TCP/IP connections, see the example in the section about message SQL1224N in Resolving problems when using databases.

    To enable shared memory:

    1. Stop the broker by running the following command, where broker is the name of your broker:
      mqsistop broker
    2. Run the following command to ensure that the broker is run in an environment with the extended memory variable exported:
      export EXTSHM=ON
    3. Restart the broker by running the following command, where broker is the name of your broker:
      mqsistart broker
    4. On the DB2 server, ensure that shared memory support is turned on. For more information, see Configuring databases for global coordination of transactions.
  2. Configure the broker's queue manager with XA Resource Manager information for each database that is involved in the transaction that the queue manager will globally coordinate. If the message flows reference message dictionaries or contain Publication nodes, you must use the same method to define XA Resource Manager information for the broker database as well as for the user databases.

    On Linux (x86 platform) and UNIX:

    1. Open the queue manager's qm.ini file in a text editor. The qm.ini file is located at /var/mqm/qmgrs/queue_manager_name/qm.ini, where queue_manager_name is the name of the broker that is associated with the queue manager.
    2. At the end of the qm.ini file, paste the following stanza:
      XAResourceManager:
      Name=DB2
      SwitchFile=install_dir/sample/xatm/db2swit
      XAOpenString=db=MyDataSource,uid=MyUserId,pwd=MyPassword,toc=t
      XACloseString=
      ThreadOfControl=THREAD
    3. On the SwitchFile line of the stanza, replace install_dir with the full path to the installation location of the WebSphere Message Broker instance.

      The switch file is supplied by WebSphere Message Broker.

    4. On the XAOpenString line, replace the following values with values that are appropriate for your configuration:
      • MyDataSource is the name of the data source to which you want to connect.
      • MyUserId must be the user name that is used by the broker to connect to the database. The user name was defined using the -u flag on the mqsicreatebroker command when creating the broker. If the -u parameter was not specified, the data source user name is the same as the broker's service user name, which was defined using the -i flag on the mqsicreatebroker command.
      • MyPassword is the password associated with the user name.
    5. Accept the default values for all the other lines in the stanza. For example, on AIX:
      XAResourceManager:
      Name=DB2
      SwitchFile=/opt/mqsi/sample/xatm/db2swit
      XAOpenString=db=MYDB,uid=wbrkuid,pwd=wbrkpw,toc=t
      XACloseString=
      ThreadOfControl=THREAD
    On Windows:
    1. From the Start menu, open the graphical administration tool for your version of WebSphere MQ:
      • Start of changeWebSphere MQ Version 6: WebSphere MQ ExplorerEnd of change
    2. Open the queue manager's Properties dialog, then open XA resource managers (Version 6) page.
    3. In the SwitchFile field, enter the full path to the switch file, as shown in the following example where install_dir is the location in which the broker is installed:
      install_dir\sample\xatm\db2swit.dll
    4. In the XAOpenString field, paste the following string:
      db=MyDataSource,uid=MyUserId,pwd=MyPassword,toc=t
    5. In the XAOpenString field, replace the values as appropriate for your configuration:
      • MyDataSource is the name of the data source to which you want to connect.
      • MyUserId must be the user name that is used by the broker to connect to the database. The user name was defined using the -u flag on the mqsicreatebroker command when creating the broker. If the -u parameter was not specified, the data source user name is the same as the broker's service user name, which was defined using the -i flag on the mqsicreatebroker command.
      • MyPassword is the password associated with the user name.
      For example:
      db=MYDB,uid=wbrkuid,pwd=wbrkpw,toc=t
    6. Accept the default values for all the other fields on the page.
  3. Stop then restart the queue manager to apply the changes because qm.ini is read only when the queue manager starts.
    To stop then restart the queue manager, enter the following commands, where queue_manager_name is the name of the queue manager:
    endmqm queue_manager_name
    strmqm queue_manager_name

    When the queue manager restarts, check the queue manager's log for any warnings that are associated with the restart. The log files are located in /var/mqm/qmgrs/queue_manager_name/errors, where queue_manager_name is the name of the queue manager that you restarted.

    When the queue manager restarts successfully, the changes that you made to qm.ini are applied.
DB2 is now configured for global coordination with a 32-bit queue manager coordinating transactions.
Now, you can deploy globally coordinated message flows to the broker.
Related tasks
Configuring globally coordinated message flows
Configuring global coordination of transactions (two-phase commit)
Related reference
Supported databases
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This build: July 31, 2007 21:16:58

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