Set transaction properties for an appserver


 

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For the transaction service we can

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.

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

New feature: WAS ND v7.0 supports WS-Transaction v1.0 and 1.1.

To set the default WS-Transaction spec level for a server to use for outbound requests that include coordination contexts...

  1. Go to...

    Servers | Server Types | WASs | servername | Container Settings | Container Services | Transaction Service

    The Transaction Service settings page is displayed.

  2. Verify the Configuration tab is displayed.

  3. To change the directory in which transaction logs are written, type the full path name of the directory in the Transaction log directory field.

    We can check the current runtime value of Transaction log directory by clicking the Runtime tab.

    If we do not enter a value for the Transaction log directory, the appserver assumes a default location in the appropriate profile directory.

    When high availability support is disabled, you do not need to set the recovery log configuration for persistent services such as the transaction service. The appserver assumes a default location in the appropriate profile directory.

    When high availability support is enabled, this default might not be visible from all servers in the cluster. For example, if the servers are in different profiles or physical nodes.

    1. Set the recovery log location for each server in the cluster before enabling high availability.

    2. Ensure that each server in a cluster has a unique transaction log directory, so that multiple servers do not attempt to access the same log file.

    3. Ensure that each server in a cluster can access the transaction log directories of the other servers in the cluster.

    For Web Services Business Activity (WS-BA) support in a high availability environment, both the transaction log and the compensation log directory for each server in a cluster must be unique.

    If we change the transaction log directory, apply the change and restart the appserver as soon as possible, to minimize the risk of problems occurring before the appserver is restarted. For example, if there is a problem and the server fails with in-flight transactions, when the server restarts, it uses the new log directory and cannot automatically resolve in-flight transactions that were recorded in the old log directory.

    We can also specify a size for the transaction logs.

  4. To change the size of transaction log files, modify the Transaction log directory field to include a file size setting.

    Use one of the following formats, 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).

    The minimum transaction log file size that we can specify is 64K. If we specify a value less than 64K, or do not specify a value, default of 1M is used.

    <!-- This format keeps the default directory -->
    ;file_size

    directory_name;file_size
    dir: //directory_name/directory_name;file_size
    /directory_name/directory_name;file_size

    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, we 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.

    See about transaction log sizes, see Manage transaction logging for optimum server availability.

  5. Reset the value of transaction timeout properties:

    Total transaction lifetime timeout

    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

    The number of seconds a transaction that is propagated into this appserver 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 must 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 situation, transactions that are affected by this timeout never time out.

    Client inactivity timeout

    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.

  6. Reset heuristic-related properties:

    Heuristic retry limit

    The number of times that the appserver 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 appserver 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 option to enable the appserver 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 appserver commits or rolls back the transaction, or depends on manual completion by the administrator.The heuristic completion direction property also specifies how a transaction is completed in the following situations:

    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 we do not select this option, configure applications individually to accept the heuristic hazard.

  7. To change the default WS-Transaction specification level to use for outbound requests that include a Web Services Atomic Transaction (WS-AT) or Web Services Business Activity (WS-BA) coordination context, select the spec level from the Default WS-Transaction spec level list.

  8. Reset other configuration properties, to suit your requirements.

    See about the properties of the transaction service, see Transaction service settings.

  9. Click OK, then save the changes to the master configuration.

  10. Stop, then restart, the appserver.

 

Next steps

If we change the transaction log directory configuration property to an incorrect directory name, the appserver restarts, but cannot open the transaction logs. Change the configuration property to a valid directory name, then restart the appserver.

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


Transaction service settings

 

Related tasks


Interoperating transactionally between appservers
Enable WAS to use an intermediary node for Web services transactions
Set Web Services Transaction support in a secure environment
Set a server to use business activity support
Manage transaction logging for optimum server availability
Set the runtime transaction service using scripting
Use the transaction service