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 undertake this task when you want to move the transaction logs
to a different storage device, or when you have to change the transaction
service settings. You must restart the application server to make
configuration changes take effect.
New feature: WebSphere
® Application Server
supports the WS-Transaction 1.0, WS-Transaction 1.1 and WS-Transaction
1.2 specifications. In practice, version 1.2 of the WS-Transaction
standard is functionally equivalent to version 1.1, so within WebSphere
Application Server, wherever WS-Transaction 1.1 is supported, WS-Transaction
1.2 is also. You can configure the default WS-Transaction specification
level to use for outbound requests if the specification level that
the server requires cannot be determined from the provider policy.
This applies to outbound requests that include a Web Services Atomic
Transaction (WS-AT) or Web Services Business Activity (WS-BA) coordination
context.
newfeat
Procedure
- In the administrative console, click . The properties of the application
server, server_name, are displayed in the content
pane.
- Click . The Transaction Service settings
page is displayed.
- Ensure that the Configuration tab is displayed.
- Optional: 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 you can specify is 64K. If you specify a value that
is less than 64K, or you do not specify a value for the file size,
the default value of 1M is used.
;file_size <!-- This format keeps the default directory -->
directory_name;file_size
dir://directory_name/directory_name;file_size
/directory_name/directory_name;file_size
For a z/OS system, you might want to reduce the size
of the transaction logs to ensure that they do not exceed the maximum
amount of data space storage that is allocated for memory mappings.
This is set through the MAXMMAPAREA parameter.
- Optional: Increase the storage
space that is used for memory mapping for transaction log files.
You can modify the MAXMMAPAREA parameter, which specifies the
maximum amount of data space storage, in pages, that can be allocated
for memory mappings of the transaction log files. There are two transaction
log files, which are named log1 and log2, and each file is allocated
1 MB. Therefore, each server needs 512 pages by default.
The
following example shows how to calculate the value for the OMVS parameter,
if you use the default size for log files:
MAXMMAPAREA = 512 x number_of_servers + (resources needed outside the application server)
where
number_of_servers is the number of controllers
that are running simultaneously, including application servers and
the deployment manager, but not the node agent.
- Optional: Disable MMAP functions.
Set the com.ibm.ws.recoverylog.spi.NoMemoryMappedFiles property.
Avoid trouble: With this option set, the behavior is the same
as it was before z/OS Version 1.9. You do not need to adjust MAXMMAPAREA.
gotcha
- From the administrative console, select .
- Click .
- Click New. Enter the information
for the com.ibm.ws.recoverylog.spi.NoMemoryMappedFiles property.
Table 1. com.ibm.ws.recoverylog.spi.NoMemoryMappedFiles
property
Name |
Value |
com.ibm.ws.recoverylog.spi.NoMemoryMappedFiles |
true |
- Click OK.
- Save your configuration and synchronize the changes.
- Optional: Review or change 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
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 (zero).
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.
- 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 option 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.
The
heuristic completion direction property specifies how a transaction
is completed in the following situations:
- The transaction manager reports a heuristic outcome for a last
participant support (LPS) resource.
- The heuristic retry limit is exceeded during the recovery of a
subordinate server in a distributed transaction.
- The transaction is imported from a Java EE Connector Architecture
(JCA) provider.
This property applies only to transactions that are in
the situations just described.
- 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.
- Optional: 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 specification level from
the Default WS-Transaction specification level list.
As version 1.2 of the WS-Transaction standard is functionally
equivalent to version 1.1, within WebSphere
Application Server wherever WS-Transaction 1.1 is supported, WS-Transaction
1.2 is also.
- Review or change other configuration properties, to suit
your requirements. For more information about the properties
of the transaction service, see the topic about Transaction service
settings.
- Click OK, then save your changes
to the master configuration.
- Stop, then restart, the application server.
What to do next
If you change the transaction log directory configuration
property to an incorrect directory name, the application server restarts,
but cannot open the transaction logs. 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. 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.