RSC/MP 7.2 Programming Manual

Application Development
HP NonStop Remote Server Call (RSC/MP) Programming Manual—522360-004
6-16
Consequences of a Primary TDP Failure
•
Determine, by analyzing the application database, whether or not the transaction
that was just committed by using TMF was actually committed to the database.
This capability is required to guard against the possibility of a system failure at the
time of a transaction commit request.
•
Save the configuration (options and parameters) when the RscConnect and
RscBeginSession functions complete successfully.
•
Save the configuration of the RscWriteRead function and every message since the
most recent RscBeginTransaction function call after the connection is regained.
Consequences of a Primary TDP Failure
System managers and application developers should be aware of these consequences
of a primary process failure:
•
All workstation sessions with the TDP are terminated. The connection failure error
code returned to the application depends on the communications subsystem in use
and does not necessarily indicate that the failure occurred because of a primary
process failure.
•
All outstanding sessions on the TDP are terminated.
•
All outstanding I/O requests by the TDP to servers are canceled.
•
All outstanding transactions in the TDP are aborted.
•
All RSCCOM sessions with the TDP are terminated and must be restarted.
•
All applications using the #RSCUMS interface receive file system error 201 in any
outstanding I/O.
•
The TDP log file, if opened, is closed.
•
All Pathway/TS IDS routers are aborted.
•
All user-written IDS requester programs receive file system error 201 from the
SEND MESSAGE statement.
Recovery From Primary TDP Failure
When a primary TDP failure occurs, the client application receives a communications
failure error. The exact nature of the failure depends on the type of communications
subsystem in use at the time of the failure. It might not be obvious whether the error
occurred because of a TDP failure or because of some other general communication
failure.
Applications should follow a predefined strategy to recover from a connection failure,
as listed:
1. Inform the user that a communications failure has occurred and that recovery is in
progress.