HP Integrity NonStop H-Series - Manual (Page 72)

recovery log for XARM, the transaction manager is made aware of the fact that the XAResource
(in this case the XARM) does not participate in 2pc protocol. If an XAResource implements a
certain marker interface, JBoss transactions assume that the XAResource does not participate in
2pc protocol. The configuration attribute xarm.onePhaseCommit in $NSASJ_HOME/modules/
com/hp/nsk/xares/wrapper/main/xarm.properties
file can be used to control the
behavior of XARM. Whereas, if the value is set to false, XARM participates in 2pc protocol.
However, the default value is true.
If the transactional resources are all TMF controlled resources, invoking a commit on the XARM
internally commits the work done by all other resources. So the data integrity is not compromised.
Normal JDBC connections participating in a transaction is viewed as a non XAResources. Hence,
connections from a JDBC T2 and T4 driver are seen as non-XAResources.
NOTE: JDBC T4 driver provides XAConnections.
As a result, when connections from T2 driver are participating in a transaction there are actually
two non-XAresources. The transaction manager needs to be instructed to accept more than one
non XAResource in a transaction. This is achieved by setting system property
com.arjuna.ats.arjuna.allowMultipleLastResources
to true in domain.xml.
Transaction subsystem configuration
The transaction subsystem is defined by the schema jboss-as-txn_1_2.xsd. This file is located
in the docs/schema folder of NSASJ installation.
NOTE: The current version of NSASJ can execute in 64-bit mode (64-bit or 32-bit is the value
for the mode selection). The default mode is 32-bit. Users can select 64-bit mode either during
installation or by switching the variable JAVA_MODE in $NSASJ_HOME/bin/config.prop file
from 32bit to 64bit and restarting NSASJ Server instances.
The following are the configuration attributes of transaction subsystem:
Table 22 Elements of transaction subsystem
Description Attributes
This attribute configures the generic transaction environment. The following
are the attributes configured in this element: core-environment
•
node-identifier : The node identifier for the JTS service. This must be
unique per JTS service, because the transaction manager uses this for
recovery. In NSASJ, since the transaction manager is not based on JTS,
this attribute is not used and has no relevance.
•
path : A relative or absolute filesystem path where the transaction manager
object store stores data.
•
relative-to : If the path is relative, then its relative to the value specified
by this attribute.
The transaction manager creates a unique identifier for each transaction log.
Two different mechanisms are provided for generating unique identifiers process-id
namely, a socket-based mechanism and a mechanism based on the process
identifier of the process. NSASJ uses a process-id based mechanism.
For Arjuna Recovery Service to run, the following are the attributes: recovery-environment
•
socket-binding : This needs to be specified as to where the recovery
manager runs.
•
recovery-listener : This is a boolean that specifies if the Arjuna
Recovery Manager needs to listen on a network socket.
•
status-socket-binding : This specifies that the status manager
associated with the recovery listener is running on this port. Every instance
has a status manager thread.
72 Configuring NSASJ