Resource Managers
When discussing commit protocols, the term "resource manager" traditionally refers to a software component that manages recoverable resources. However, in CA IDMS this term refers to both the resource manager and the interface used to communicate with it.
The DCMT DISPLAY DISTRIBUTED RESOURCE MANAGER command can be used to obtain a list of all resource managers known to a central version or to display the details of a specific resource manager.
Note: For more information about DCMT commands, see the CA IDMS System Tasks and Operator Commands Guide.
CA IDMS Resource Managers
When one CA IDMS system accesses another, each one becomes a resource manager to the other. On the front end, the partner system is identified by its node name and an interface name of "DSI_CLI"; on the back end, the partner system is identified by its node name and an interface name of "DSI_SRV". A central version may have knowledge of several resource managers whose interface name is DSI_CLI or DSI_SRV, since it may communicate with several CA IDMS systems. Furthermore, a central version may have knowledge of two resource managers with the same node name, one for each of the two interfaces, since a system can act as both front-end and back-end to another system.
External Resource Managers
When a CICS system is used to access a central version, it becomes a known resource manager on the backend with a node name that is the concatenation of "CICS" and the CICS system name and an interface name that is specified by the IDMSINTC interface module through which access is made.
When RRS is activated within a central version, it is known as a resource manager whose node name is that of the local system and whose interface name is "RRS_RMI".
Note: For more information about CICS and RRS, see the CA IDMS System Operations Guide.
Interfaces and Exits
To participate in a two-phase commit operation coordinated by CA IDMS, a resource manager makes its existence known by registering with the local transaction manager. When registering, the resource manager interface identifies exit routines to be invoked by the transaction manager during the commit process. In this way, the resource manager interface acts as a bridge between the local transaction manager and the resource or transaction manager to which it provides access. It is the resource manager interface's responsibility to forward Prepare, Commit, and Backout directives and return appropriate responses to the local transaction manager.
When a resource manager's exit is invoked, it returns outcomes that are similar to those outlined in 20.2.8, “Transaction Outcomes". For example, a resource manager's prepare exit can return a FORGET outcome to signify that it has made no changes within the scope of the transaction and therefore need not participate in the second phase of the commit operation.
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