WebSphere Application Server Version 6.1 Feature Pack for Web Services
             Operating Systems: AIX, HP-UX, i5/OS, Linux, Solaris, Windows, z/OS

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Configuring transaction properties for an application server

You can view or change settings for the transaction service. For example, you can change the location or default file size of the transaction log files, change transaction timeout properties, or change heuristic-related properties.

About this task

The transaction service is a server runtime component that can coordinate updates to multiple resource managers to ensure atomic updates of data. Transactions are started and ended by applications or the container in which the applications are deployed.

You might perform this task when you want to move the transaction logs to a different storage device, or when you need to change the transaction service settings. You must restart the application server to make configuration changes take effect.

Procedure

  1. In the administrative console, click Servers > Application Servers > server_name . The properties of the application server, server_name, are displayed in the content pane.
  2. Under Container Settings, expand Container Services, then click Transaction Service to display the properties page for the transaction service, as two notebook pages:
    Configuration
    The values of properties defined in the configuration file. If you change these properties, the new values are applied when the application server next starts.
    Runtime
    The runtime values of properties. If you change these properties, the new values are applied immediately, but are overwritten with the Configuration values when the application server next starts.
  3. To review transaction-related configuration properties, ensure that the Configuration page is displayed.
  4. [AIX HP-UX Linux Solaris Windows] [i5/OS] Optional: If you want to change the directory in which transaction logs are written, type the full path name of the directory in the Transaction log directory field. You can check the current runtime value of Transaction log directory, by clicking the Runtime tab.

    If you leave this field unset, the application server assumes a default location within the appropriate profile directory.

    When using WebSphere Application Server without high availability support, you do not need to set the recovery log configuration for persistent services (such as the transactions service). The application server assumes a default location in the appropriate profile directory. When high availability support is enabled, this default may not be visible from all servers in the cluster (for example, if they are in different profiles or physical nodes.) Because of this behavior, configure the recovery log location for each server in the cluster before enabling high availability. You must also ensure that each server in the cluster has a unique log directory, to avoid attempts by multiple servers to access the same log file.

    You can also specify a size for the transaction logs, as described in the following step.

    Note: If you change the transaction log directory, you should apply the change and restart the application server as soon as possible, to minimize the risk of problems occurring before the application server is restarted. For example, if a problem causes the server to fail (with in-flight transactions), the server next starts with the new log directory and is unable to automatically resolve in-flight transactions that were recorded in the old log directory.
  5. [AIX HP-UX Linux Solaris Windows] [i5/OS] Optional: To change the size of transaction log files, modify the Transaction log directory field to include a file size setting. Use the following format, where directory_name is the name of the transaction log directory and file_size is the disk space allocation for the transaction log files, specified in kilobytes (nK) or megabytes (nM). If you do not specify a value for the file size, the default value of 1M is used.
    directory_name;file_size
    [AIX HP-UX Linux Solaris Windows] For example, for a Windows system, the following entry specifies that transaction log files are created in the directory c:\tranlogs with a size of 2 megabytes.
    c:\tranlogs;2M

    In a non-production environment, you can turn transaction logging off by entering ;0 in the Transaction log directory field (do not enter a directory name). Do not turn transaction logging off in a production environment because this prevents recovery after a system failure, and therefore data integrity cannot be guaranteed.

    For more information about transaction log sizes, see Managing transaction logging for optimum server availability.

  6. Optional: Review or change the value of transaction timeout properties:
    Total transaction lifetime timeout
    Type the number of seconds to allow for a transaction that is started on this server, before the transaction service initiates timeout completion. If a transaction does not begin completion processing before this timeout occurs, it is rolled back. A value of 0 (zero) indicates that this timeout does not apply, and therefore the maximum transaction timeout is used instead. Application components can override the total transaction lifetime timeout for their transactions by setting their own timeout value.
    Maximum transaction timeout
    Type the number of seconds a transaction that is propagated into this application server can remain inactive before it is ended by the transaction service. This value also applies to transactions that are started in this server, if their associated applications do not set a transaction timeout and the total transaction lifetime timeout is set to 0.

    This value should be equal to or greater than the total transaction lifetime timeout. A value of 0 (zero) indicates that this timeout does not apply. In this case, transactions that are affected by this timeout never time out.

    Client inactivity timeout
    Type the number of seconds after which a client is considered inactive and the transaction service ends any transactions associated with that client. A value of 0 (zero) indicates that there is no timeout limit.
  7. Optional: Review or change heuristic-related properties:
    Heuristic retry limit
    The number of times that the application server retries a completion signal, such as commit or rollback. Retries occur after a transient exception from a resource manager or remote partner, or if the configured asynchronous response timeout expires before all Web Services Atomic Transaction (WS-AT) partners have responded.
    Heuristic retry wait
    The number of seconds that the application server waits before retrying a completion signal, such as commit or rollback, after a transient exception from a resource manager or remote partner.
    Enable logging for heuristic reporting
    Select this property to enable the application server to log "about to commit one-phase resource" events from transactions that involve a one-phase commit resource and two-phase commit resources.
    Heuristic completion direction
    Select the direction used to complete a transaction that has a heuristic outcome; either the application server commits or rolls back the transaction, or depends on manual completion by the administrator.
    Accept heuristic hazard
    Select this option to specify that all applications on this server accept the possibility of a heuristic hazard occurring in a two-phase transaction that contains a one-phase resource. This setting configures last participant support (LPS) for the server. If you do not select this option, you must configure applications individually to accept the heuristic hazard.
  8. Review or change other configuration properties, to suit your requirements. For more information about the properties of the transaction service, see Transaction service settings.
  9. Click OK and save.
  10. Stop then restart the application server.

    If you change the transaction log directory configuration property to an incorrect directory name, the application server will restart but be unable to open the transaction logs. You should change the configuration property to a valid directory name, then restart the application server.

    If you are running the application server as non-root, modify the permissions on the new transaction log location. If you want to use peer recovery of transactions on a shared device with non-root users, make sure that your non-root users and groups have matching identification numbers across machines




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Last updated: Nov 25, 2008 2:35:59 AM CST
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