Copyright © TIBCO Software Inc. All Rights Reserved
Copyright © TIBCO Software Inc. All Rights Reserved


Chapter 3 Administering a Distributed Environment : Implementation of Distributed Data

Implementation of Distributed Data
Supported Inter-connections
If connectivity is established between various TIBCO Object Service Broker systems, users can access data defined on systems other than the one in which they are currently working. When the correct environment is established, TIBCO Object Service Broker ensures that allowable accesses are made to data at the appropriate location.
The inter-connected nodes can be running on any combination of TIBCO Object Service Broker supported operating systems, z/OS, Windows, or Solaris, as shown in this diagram:
 
Similar connectivity is supported between TIBCO Object Service Broker components: Data Object Broker, Execution Environment, external database servers, and the client interface. For more information about supported connections, refer to TIBCO Object Service Broker for Open Systems Installing and Operating. For complete details about setting up the communications requirements for this type of distributed configuration, refer to Installing and Operating for your operating environment.
Steps Taken to Access Remote Data
The following steps are taken when a request is made from an application for data that is remote to the application:
1.
2.
3.
Ensuring Data Integrity
TIBCO Object Service Broker Fail Safe processing ensures that when a transaction ends or a commit is issued, data updates across multiple nodes are handled as if the data were on one node. To make the updates, the transaction must obtain locks for the tables on each node independently.
A single transaction can access data in more than one external database, that is, DB2, CA‑IDMS, and so on. However, if more than one external database server is used to update data within a single transaction, TIBCO Object Service Broker cannot ensure data integrity.
Locating the Data
For a given table access, the location of the data being retrieved or updated is determined by the application providing a value, implicitly or explicitly, for the location parameter of the table. The value used is the node name for the TIBCO Object Service Broker system where the required data resides. At installation time, a TIBCO Object Service Broker system is assigned a node name using the Data Object Broker parameter NODENAME.
Order of Evaluation to Determine Location
When data is accessed by a rule, the location of the data is determined by a defined order of evaluation. The evaluation is based on a parameter defined as CLASS=L (location) in the table definition. This evaluation continues until either a non-null location value is found or the end of the list is reached. The order of evaluation is given in the following illustration:
Server Access
If the peer server that is being used to access remote data is busy or if the connection to the peer server fails, one of the following exceptions is raised:
SERVERBUSY Exception
The SERVERBUSY exception is raised for the following reasons:
Control is passed back to the rule, allowing the rule to try the transaction again.
SERVERFAIL Exception
The SERVERFAIL exception is raised if a transaction is in progress when the connection to the peer server breaks or the peer server fails. Control is passed back to the rule for transaction cleanup.
The exceptions SERVERERROR and SERVERFAIL are also used for access to external databases such as DB2, IMS/DB, or CA‑IDMS. For more information about their use by the external database servers, refer to the appropriate TIBCO Service Gateway manual.
Binding of Data and Rules
When the remote data and rules are first accessed, the security data and site rules are bound at the remote node in the peer server storage. If changes are made at the remote node that affect security or the site rules (including event and location rules), the peer server storage must be refreshed by shutting down and restarting the server.
For information about starting and stopping a peer server, refer to Installing and Operating for your operating environment. For more information about binding, refer to Chapter 5, Binding.
See Also
For information on configuration requirements between nodes for distributed data processing, refer to Installing and Operating for your operating environment.

Copyright © TIBCO Software Inc. All Rights Reserved
Copyright © TIBCO Software Inc. All Rights Reserved